QuoteGood advice in general.
However, depending on how crafty the users are ideally you would need to use a switch with DHCP-snooping and ARP inspection to prevent them from changing MAC or configuring static IP's to work around the limitations on the dynamically allocated ones.
Another solution would be to used a separate VLAN and apply limits on the entire subnet.
Works for me so far. Have not thought of that, not a network expert though.