Addition to the replies before mine, even if you could use CF - it's a joke, it's easily bypassable and there's tons of methods to do it (i.e. the most common we used is huge botnets with simply emulated browsers sending tons of req/s, and that's just the 'public' one, there's tons of private ones we used to write ourselves that were much complex but needless as the one I mentioned before worked just fine)
