Public does nothing to do with static. Both public and local IPs may be static or dynamic. Public IP means, it is accessible FROM internet directly. Opposite to public IP is local (or private) one. Machine with local IP has access to internet (ussualy using NAT technique), but other machines from internet are not able to see it. It means, if local IP is assigned to your machine, it is invisible for game clients trying to connect from outside of your LAN. Check the IP (in network adapter properties) or using command ipconfig. if your IP address starts with 10. 172. or 192. - it is local IP address and you will not be able to host games.