in most common case, NAT will be enabled on your dsl router/modem. foward port 3389 (default remote desktop port) to your server's internal static ip. unless your server has public ip address you will need to port foward. in your case, it would be under virtual server in your router/modem. also, like the others said make sure to turn on remote desktop and select users allowed. users must have a password to be able to connect.