https://docs.microsoft.com/en-us/windows-server/remote/remote-desktop-services/clients/change-listening-port
Applies to: Windows 10, Windows 8.1, Windows 8, Windows Server 2019, Windows Server 2016, Windows Server 2012 R2, Windows Server 2008 R2
When you connect to a computer (either a Windows client or Windows Server) through the Remote Desktop client, the Remote Desktop feature on your computer “hears” the connection request through a defined listening port (3389 by default). You can change that listening port on Windows computers by modifying the registry.
- Start the registry editor. (Type regedit in the Search box.)
- Navigate to the following registry subkey: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp
- Find PortNumber
- Click Edit > Modify, and then click Decimal.
- Type the new port number, and then click OK.
- Close the registry editor, and restart your computer.
The next time you connect to this computer by using the Remote Desktop connection, you must type the new port. If you’re using a firewall, make sure to configure your firewall to permit connections to the new port number.
To add a new RDP Port to the registry:
Set-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp' -name "PortNumber" -Value 3390
New-NetFirewallRule -DisplayName 'RDPPORTLatest' -Profile 'Public' -Direction Inbound -Action Allow -Protocol TCP -LocalPort 3390
