Here's the log for when I try to connect to my roommate.

0.004 2017-04-12 15:58:53; Factorio 0.14.22 (build 25342, win64, steam)
0.004 Operating system: Windows 10 (version 1607)
0.004 Program arguments: "S:\SteamLibrary\steamapps\common\Factorio\bin\x64\Factorio.exe"
0.004 Read data path: S ...

Yeah I just tested it with two more people away from here, both of us can host games that connect over the internet for other players to join, but not on local LAN, and neither of us can connect to eachother's games via local or internet. There is no setting in my router that i can toggle, to fix ...

Left town for a few days with my roommate, came back and we tried to play Factorio. No Factorio updates, no Windows updates. Before we left, we had played Factorio the day before, which was around the 7th.

Removed windows/(modem/router) firewalls from the equation. DMZ, port forward, turned off ...