Nelson’s tale of tracking down devices using his home network. I’ve had to do this myself a few times and it’s no fun.
So then I have to get clever to find the device. nmap’s TCP fingerprinting is helpful for figuring out what OS that IP address is running. For the Playstation that showed that it was FreeBSD, and I vaguely remembered that Sony bizarrely used FreeBSD for its OS and that helped me track it down. nmap can’t detect the Kindle OS via TCP fingerprints. For that device I was left with wireless signal strength in my router display. I guessed maybe it was the Kindle by the time it registered for DHCP then physically carried the Kindle nearer to the router to determine the mystery IP address’ signal strength got stronger. Ridiculous.