> if you take someone elses public IPv4 address and they're using it, neither one of you will be functional, and they will come knocking on your door. Sure, bu

> if you take someone elses public IPv4 address and they're using it, neither one of you will be functional, and they will come knocking on your door. Sure, but if I have the IP address 1.2.3.4 I can have lots of unique physical things have that publicly routable IP address and have them all work if I do it right. https://en.wikipedia.org/wiki/Anycast https://en.wikipedia.org/wiki/Anycast