Blocking Internet Access on the fly
First, some context. I'm in a university environment, under a central IT department. For the most part I have control over the School's image, Group policy, and physical hardware. Not so much when it comes to an network infrastructure and network services.
Now, for my question. I have a mobile laptop lab, which instructors borrow when their class needs the laptops. During exams the instructors ask if the internet can be disabled so ensure student integrity. I need a quick way to disable the internet access while still allowing connection to some network shares. Most people say configuring a proxy in Group policy or something like that but I rather something along the lines of a script that I can run to "turn it off" and script to "turn it back on." Because the laptops are wireless, group policy timing can be finicky and I only need to turn it off for a few hours at most.