How to use Oracle VirtualBox' remote display feature?
Solution 1:
You need to connect to the host rather than the guest. I would split the problem into two and suggest firstly you try and connect on your host to the guest with something like
rdesktop localhost 3390
and see if you get a connection.
If that works, then go to your windows machine and connect with "Remote Desktop Connection" specifying the hostname and the connection separated by a colon(:)
so something like
myserver:3390
If this still doesn't work, what sort of errors are you getting? Is the connection rejected or does it time out. Can you turn on logging on your firewall, or turn off the firewall altogether briefly to check its not a firewall problem.
Solution 2:
First you need to make sure you have the VirtualBox Extension Pack installed. Get it from here: https://www.virtualbox.org/wiki/Downloads
Once this is installed, enable the virtual display for your VM. Now you need to connect with a rdp viewer to the host's ip address.
But if you are connecting to the local host then according to the virtualbox help documentation:
When connecting to localhost in order to test the connection, the addresses localhost and 127.0.0.1 might not work using mstsc.exe. Instead, the address 127.0.0.2[:3389] has to be used.