[Dagwoodie]

I had a similar thing happen to a friend of the family whose business I provided IT services for. He had 2 servers and 2 rack mounted UPS's and a handful of other devices that all fit into the same rack. One day I needed to do some maintenance that required shutting one of his servers down. This was a backup server that wasn't actually used for anything as long as the primary was up and functional.

The problem was that as soon as I shut the backup server down, his entire network stopped working. I was trying to the maintenance over a VPN, so immediately I lost access. I don't really have a clever way of telling this right now, but after a lot of frustration trying to figure out the problem remotely (and wondering if someone had pwn'd his servers and was using the backup server to MITM all his traffic) I drove out there and noticed the problem right away. The UPS that the backup server was connected to was faulty, what was happening was that once the server was no longer pulling electricity from the faulty UPS, it failed to power the other equipment that was plugged into it, one of those things being a critical switch. As soon as the server was powered back on, all the other equipment attached to it immediately powered up too.

[yellowapple]

Sounds like one of those surge protectors that control the power to other devices based on whether or not a central device is powered on. Some powerbars for home theater setups have a similar feature; if you turn off the TV, all the other stuff turns off with it, and if you turn on the TV, everything turns back on.

Weird that a rackmount UPS would have that sort of feature, but hey, it's possible.

[Fomite]

I have a rackmount UPS that was expressly intended for AV purposes that does that.