We are running a hotspot network with DHCP running, handing out public IP addresses, and it appears that one client is grabbing all of our IPs. The awkward thing is that all of the addresses in the Leases show the MAC address as 00:00:00:00:00:00, so there is truly no way to block this it looks like. Are there any ideas on what could cause this? Any ideas on how to block this?