How to prevent VPS users from using IP that doesn't belong to them?

[rocka]

I am trying to start a small VPS hosting company. I want to know what's the easiest way to prevent VPS user from adding IP that wasn't assigned to them to their VM? Any suggestions?

[donaldbren]

If you have access to the switch, maybe you can create static ARP entries so that the IPs can only work on specific MAC addresses.