Whitelist IPs: Use Windows Firewall to restrict RDP access to specific IPs only
If you always connect from the same IP address, or IP address range (or the range your ISP uses), you can restrict RDP access to those IPs through the Windows Firewall (Inbound Rules for Remote Desktop which may consist of multiple rules, TCP-in and UDP-in, and Remote Desktop-User Mode and Remote Desktop Services-User Mode). Go to the scope tab of the inbound firewall rule and add your IP addresses to the Remote IP list for both rules. This is a great method to secure RDP when always working from the same location but it won’t work if you plan to access your Remote Desktop Server while traveling because you won’t be using the same static IP address.