Way to prevent user change his IP in Mikrotik

Using Winbox

• click your NIC that provide local bandwidth, in interface command
• Set ARP=Reply-only
• Set B/W limit to client IP
• Remember and note your MAC address of your client NIC
• go to the IP->ARP
• look at the first column, is there a letter "D" ?? if yes, your ARP address was sign to dynamic
• right-click at the address, choose make static
• now you can change the MAC Address manually if you want :D

Good luck !! :D