All of those are good points. But a surprising number of people can't get to the starting point 2^(32-23)=512. I usually subtract 2 and say 510. No IPs are rese

All of those are good points. But a surprising number of people can't get to the starting point 2^(32-23)=512. I usually subtract 2 and say 510. No IPs are reserved for multicast. Maybe you meant broadcast?