The Remote Desktop client attempts to connect to port 3389 on the server machine.
If you want it to connect to different port you have to specify it in the address, eg. 100.10.10.1:3390
Is there way to change the default port it tries to connect to so that you don't have to specify it in the address?
Best Answer
You can change the portnumber by modifying the registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp\PortNumber
In mstsc you can connect to the host just the way you expected. (eg: 100.10.10.1:3390).