So I’m at my favorite net-enabled coffee shop and the connection is just sucking wind. It gets this way from time to time. I fire up “ettercap” to see if I can figure out why. Huh. There’s a computer at 192.168.1.106 constantly firing off requests on port 445 to random IPs. I mean dozens and dozens per second. I look it up and find out that port 445 is a Windows service of some sort, a favorite of worms. So somebody here has a badly worm-infected computer that is hosing the connection for everybody. Thanks.
I wish I was l33t enough to know how off the top of my head to identify who it was and tell them they have a problem (and they are causing problems for everyone else), or else just knock them offline.
Anyone got suggestions?
UPDATE: via the ancient technique of “walking around and talking to people” I managed to find the person whose IP it was. He was grateful to find out his machine was infected.