This evening I had a mysterious network outage. I went to investigate and found the cable ever-so-slightly loose from its socket. (In a corner of a room that nobody had been in to disturb it.) I clicked it in, the lights came on, and it was all fine.
Later on, the network goes again. I go and look and everything has the proper indicator lights. The modem is chatting away to the Internet, the router is talking to both the modem and the network. The router configuration screens all come up okay. But tracert stops dead after the router. Odd. I reboot the router and the modem. Still nothing.
Then, the ring mains circuit breaker trips. Everything is quiet. The engines go dead. I have a look around. Nothing is out of the ordinary. I flick it back on, and the computers bleep back into life. Everything boots up and the Internet is available. Nothing was ever wrong.