Remote Desktop Protocol - Wikipedia

3389 port tcp or udp Actually, Remote Desktop requires TCP port 3389 to be open. Also, opening UDP port 3389 enables acceleration since RDP 8.0 (e.g. Windows 7 with RDP 8 Update, Windows 8, or Windows 10). In other words, if you use the former version of RDP (before RDP 8.0), then TCP will be the only protocol that can be used..

3389 port  UDP port 3389 enables acceleration since RDP 8.0. To use RDP, you need to open port 3389 on your Windows firewall and your router. This will allow incoming and outgoing traffic on that port and enable you to connect to your PC remotely.

3389 port service  This article provides a comprehensive guide to RDP network ports, with a focus on TCP and UDP protocols.