I'm helping a relative out at his office, he's got website filtering enabled on his router (a D-Link DIR-600) to block Youtube and Facebook, yet somehow his employees are able to access these sites anyways. Each of them has a company-supplied laptop that they use to access the network wirelessly. They have full control over the laptops and can install and access practically any portion of it (this is another issue, but I'll address that later).
I've checked settings on the browsers they use (Firefox and Chrome), and they don't appear to have changed anything, and clearing out browser history/cookies doesn't seem to work either, so I'm guessing the problem must be further in.
EDIT: I brought a laptop from home and connected to their network to see what was up. I tried entering the url straight into my browser and was promptly blocked, but the Facebook page that I already had open and logged into my personal account would refresh just fine and I could even visit friends pages.
Any ideas on where I could look next?