Good morning.  Three friends and I are getting together this weekend for a SINS session.  Two machines are mine, and two belong to one of the other guys. He brought his over today and we set them up and tested for connectivity and functionality this morning so that we don't have to waste time the day of the actual get together.

All four PCs are connected to the same gigabit, 8-port switch.  During testing we discovered that three PCs can host, but one can't (the other three see the game in the LAN list, but instantly disconnect when they try to join the game.  The three that can successfully host are Windows 7sp1.  The one that can't is Win8.1.  I've confirmed that all firewall settings are identical between the four machines.  Any thoughts?

View from the PC in the hall (you can see that PC and the monitor on my main PC): http://i.imgur.com/UgX5k3H.jpg

View the office looking out to the hall (you can see that PC and the other two in the office): http://i.imgur.com/4Xa2tb0.jpg

Thanks for any ideas,

pat----