How to shut down this sonic wall for the school?

Answer 1

If you are the administrator you can. However, the school really needs it to protect the internal computers for scammers, predators and fools who would try to get to the student records, school financial information or simply to use the computers as a jumping point for other attacks elsewhere.

Answer 2

If you're really worried about getting around the filter, use a proxy-browser. Just search it in Google. But otherwise, don't mess with the Sonic Wall, really. That's grounds for expellsion in most schools.