Gather around the server script kiddies for I have a scary tale of woe. What makes this story all the more scary is that it is true.
Years ago, late at night I was startled awake by the buzzing and alarms of my cell phone, as a series of SMS messages came through from various monitors I had in place warning me that a website I managed was down.
I stumbled to my home office and fired up my laptop to see what the problem was. The site was down, nothing via web browser, or port 80, but the server was still up.
My first thought was that it might be a data center issue, maybe down for maintenance, but when I accessed our providers systems there were no issues and according to their control panel our servers were all operational.