Can't get Remote Desktop to work to Win 8.1 Pro X64 system

I have a Win 8.1 Pro X64 system that I'm trying to RDT (remote Desktop) to but can't seem to make it work. I have it working fine to my Win 7 Pro X64 system sitting right next to it.

I've setup Port Forwarding in the Router the same as it's set for the Win 7 system, just using a different port. When I then try to make a RDT connection to it, it never connects. I've tried it from within my home LAN (192.168.1.x) and from a public network. Both work correctly to the Win 7 Pro X64 system but not to the Win 8.1 Pro X64 system.

Looking for some way to debug this and see what it going wrong.

Both machines have the Windows Firewall setup to Pass Remote Desktop and Remote Desktop Connection.
As I said, the router port forwarding is setup the same for both, just using different ports (3390 for W7 and 33390 for W8).

All ideas greatly appreciated.


Hmmm, I wonder what would happen if I made the W8 system use 3390 (the default port for RDT) and 33390 for the W7 system? Guess I'll give that a try.

Just use Teamviewer. Delete the ipen ports in the router you put in.

I don't want to use TeamViewer, I want to get Remote Desktop to work.

I looked at

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp
PortNumber

and the value was 3389, not 3390. Used that and it worked correctly on my internal home network. Now tio see if I can get it working from an external network.