I'm not exactly sure how the web filter iBoss works but it doesn't seem to be installed on all the computers at my school so I was thinking it probably handles connections directly at the DNS level and also because if resources on a website are trying to be loaded from outside websites or servers that are blocked i-Boss filters them as well. I was wondering if I changed the DNS on the NIC whether or not iBoss wouldn't be able to filter search queries, websites, etc. No I don't plan on getting myself in trouble, I ask purely out of curiosity and because it interests me.
The iBoss blocks DNS outgoing requests which would block secure sites users are trying to connect to that fall under the iBoss filtering policies.
If you are experiencing iBoss not filtering secure sites, try to flush the DNS cache by re-booting the computer and the iBoss unit.
So yes, it sounds like changing your DNS servers will bypass it.
Assuming you have sufficient control over the computer to change the DNS settings, such as your own personal device, that is.