This is a horrible interview question for all but a tiny handful of jobs: Is 300.168.0.123 a valid IPv4 address? ...but it is a great late night fun trivia

This is a horrible interview question for all but a tiny handful of jobs: Is 300.168.0.123 a valid IPv4 address? ...but it is a great late night fun trivia question about "how can adding one character to that address make it into an address accepted by many tools".