My home network has 4 wired computers (all Win 7 Pro) which I access using Remote Desktop Connection when I'm going to be out of my office for extended periods. I have done this before, but it's been a while. The steps I take to get it running are:
1. Go to control panel - System - Remote Settings and click on the radio button to allow connections.
2. In windows firewall a create a rule for allow inbound connections on a port other than the default port
3. I change the RDP port in the registry to the same value set in 2.
4. I set up port forwarding rules in my dsl router to forward incoming connections to the correct ports.
I have verified that the above works connecting to one of the computers from outside my home network. Inside my home network I am able to connect using RDP to 3 or the four computers. For some reason one of them isn't working; I just never get a response from it. What else can it be?