How to Change RDP port in Windows Server via Powershell CLI
Open Powershell as Administrator
Change RDP port:
Set-ItemProperty -Path "HKLM:\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp\" -Name PortNumber -Value 3391
Check current port:
(Get-ItemProperty -Path "HKLM:\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp\" -Name PortNumber).PortNumber