how to prevent clients from going to other “fake” DHCP Server,

Hi there..

I think i discovered my problem.

I?m sysadmin, at a university and some students are working whit vmware creating dhcp and dns Servers for a task.

how can i prevent other dhcp or dns servers from been set on the network ?

Blocking the student PC from reaching the network while working on that task (firewall,some policy ??)

thanks in advanced