[drexlspivey]

So the students are advanced enough to change their firefox config but not enough to change their DNS in their computers?

[Tushon]

There are plenty of ways to lockdown the ability to change DNS settings on your enterprise computers (you can also lockdown Firefox with the right deployment) and you can block port 53 traffic to outside your network, but you can't block DNS -> HTTPS w/o the interventions cited above.