Q. How can I enable a connection to a machine over RDP and through a firewall?

A. RDP operates over TCP port 3389. Therefore, to enable connectivity to any machine on the network through a firewall you must open this port. Alternatively, if you have to connect to a particular system on a LAN, configure port forwarding on the firewall to send traffic from port 3389 to the specific computer to which you want to connect.