I've just spent 2 hours trying to fix a network problem and the network was brought down... by a single computer.
A couple of days ago, we got a new router, a Linksys WRT610N to replace our Cisco 857W (WRT610N is a lot more easier to configure than the 857W). I got it mostly set up and I took down the network to get it to work with the new router. Before, we had a single cable from the router to a switch and it worked at 100mbps, it worked but it wasn't the best system. The new system, there is a single uplink to each of the rooms (whereas the rooms were plugged into the downstairs switch) and do to the WRT610N have a gigabit switch (which has been tested to 116MB/s), each room has a gigabit uplink (only 3 rooms need the uplinks, rest works on wireless).
The new system after a bit of fiddling was working great (except for the new modem, but that got solved the day after and that's working great... except when the power goes off) however overnight we had a brief power outage (enough to knock the safety switches) which also make the modem turn off until you hit a button at the front (which is very annoying). I was woken up to solve the problem and I turned on the modem. A few minutes later, the entire wired network (wireless was functioning fine) goes down and I can't work out why. I unplug it and the modem to see if that helps (it doesn't) then tried reseting the config to defaults (that didn't work either). Thinking the LAN ports on the router had blown, I unplugged everything and tested each port with a laptop, all working. Plugged in each LAN cable (Starting from room 3 down to room 1) and when I plug in room 1's switch, the wired network does the same thing. Eventually I found my father's server seemed to be spamming the network and was causing the router to strain under the load, one unplugging of the power cord and the network was up and running again.
Do any of you have networking hell stories to share?