For a while my computer has had the annoying habit of rebooting whenever I tell it to shutdown. That doesn’t sound so bad does it? What it means is that I need to be present at the machine if I want to turn it off. I can’t tell it to turn off after midnight or after a hour of being idle (and forget suspend, that’s never worked right).
On and off for the past few weeks I’ve been crawling through the system logs and BIOS trying to find an ACPI error or other warning that would explain why the kernel feels like it needs to reboot. Then on a whim I turned off Wake On LAN.
I had turned on WOL because I thought it would be cool if I could turn on my computer from another computer, netbook, or mobile device before I go downstairs to use it. It turns out that WOL on this particular motherboard doesn’t work the same as other computers. Usually you need to send a magic packet to wake a computer up, but for some reason my computer wakes up with a simple ping or any other traffic sent to it’s address.
Turning off WOL did the trick, the computer actually shuts down when I tell it to shutdown. So, either there is some traffic from the network directed at my machine or the same flaw that makes the motherboard wakeup without a magic packet keeps it from powering down.