Firstly, let us dissuade you from thinking your IT department, your hardware firewall or your hosting company does this for you. You hardware firewall doesn't block attacks that appeared anytime after they were first deployed however long ago that was, the IT guys do not have the time to be constantly watching the latest outbreaks and reacting in time and your hosting company makes more money the more traffic you have, so none of these will work. We know cause we used to think the same way, until we had to do 3 site recoveries in 24 hours about 5 years ago. Anyway what does work?