Been there - on a Nuclear Power Plant
similar story. We had built the first image for a power control plant that was to hook up and manage a number of nuclear power stations. Thanks to the local telecoms muppets we were way behind schedule and hadn't started our clone of the standard image on to the workstations. Until one evening, the system came online, and we started doing a long suite of tests with the power station. And left for the night.
When I got in next morning all hell had broken lose. People were going mental and the site managing director wanted to rip me a new one. It seems that we had sent a "SCRAM" command to the reactor. For those not knowing, this shuts down the reactor hard and fast, and can take months to recover from. I asked for an hour to find out what was going on.
With the hour up, we went back in to the meeting for round two of lets beat up the IT techies. Where I asked if "Jerry" was joining us (not his name). Jerry was there. He was from the company building the reactor control equipment that we connected to. His work was behind schedule, caused by our work being behind schedule. So I asked him how come all the PC's in the control office were all up and running. He then somewhat sheepishly admitted that he had, over night, cloned our working machine that was doing tests and installed the image over all the new machines that we had not yet configured. He then started doing some commands to see if the reactor was behaving.
The problem was that he had not changed the unique addresses of the workstations. This is pore internet, so they were sort of like IP addresses but exactly the same. The protocol allowed the boxes to come up. So Jerry booted all 8 boxes. And sent a command to the reactor.
Now the protocol was: Send a command. Reactor sends the command back for confirmation. The PC then replies, yes, that's what I want, and the reactor says OK, here is the result. Trouble was, one PC said yes, that's fine but 7 said - no, we didn't ask for that. So the reactor does another round of checks. And agsin 1 says yes and 7 say no. The reactor then assumes it's under attack and shuts itself down. Hence the scam command.
Fortunately we didn't cause too much damage as we were only talking to the control test rig, not the actual reactor. But it did get me the missing lock on our computer room and Jerry a flight home. Oh, and we got our names on rather splendid mural at the entrance hall for having saved the say!
The explosion icon, well, its obvious.