Allows this computer to receive inbound Remote Desktop requests. To do this Windows Firewall opens TCP port 3389.If you enable this policy setting Windows Firewall opens this port so that this computer can receive Remote Desktop requests. You must specify the IP addresses or subnets from which these incoming messages are allowed. In the Windows Firewall component of Control Panel the "Remote Desktop" check box is selected and administrators cannot clear it.If you disable this policy setting Windows Firewall blocks this port which prevents this computer from receiving Remote Desktop requests. If an administrator attempts to open this port by adding it to a local port exceptions list Windows Firewall does not open the port. In the Windows Firewall component of Control Panel the "Remote Desktop" check box is cleared and administrators cannot select it.If you do not configure this policy setting Windows Firewall does not open this port. Therefore the computer cannot receive Remote Desktop requests unless an administrator uses other policy settings to open the port. In the Windows Firewall component of Control Panel the "Remote Desktop" check box is cleared. Administrators can change this check box."
Network\Network Connections\Windows Firewall\Standard Profile
Machine
At least Windows XP Professional with SP2
HKLM\SOFTWARE\Policies\Microsoft\WindowsFirewall\StandardProfile\Services\RemoteDesktop!Enabled; HKLM\SOFTWARE\Policies\Microsoft\WindowsFirewall\StandardProfile\Services\RemoteDesktop!RemoteAddresses
windowsfirewall.admx