Remote Desktop Protocol TCP 3389
If you want to use Remote Desktop to connect to a server or Windows PC you may need to open a port in your router or firewall to get it to work. The port to open that allows the use of Remote Desktop is port TCP 3389 also known as RDP or the RDP Protocol. You may also need to alter the settings on your Windows firewall or other personal firewall to allow TCP 3389 to pass through.