If i understand correctly, your offenders are emplyees not just students. I had to deal with this recently and took a different aproach:
It works, and I'm sure there are better methods as well. now the end-user can just double click 'on' or 'off' to change that PC I also have a static assigned to that PC. I changed a bit of info to hide computer names and IP's. Psexec \\computer_name netsh interface ipv4 set address 'Local Area Connection' static 155.155.155.236 255.255.254.0 ** Okay, no longer has internet access, have a nice day. ** This will turn OFF the internet on ** (155.155.155.236 Static) by setting the gateway to 0.0.0.0 ** Psexec \\computer_name netsh interface ipv4 set address 'Local Area Connection' static 155.155.155.236 255.255.254.0 ** Okay, now has internet access, have a nice day. Have at 'er if it works for ** This will turn ON the internet on ** (155.155.155.236 Static) by restoring the gateway. You would need psexec, but that's easy to get.
'internet on' and 'internet off' that I supplied to the person that is responsible for that PC. but I've done something similar for a particular PC here that does not need internet access 90% of the time, but occasionally does.