"ClearCloud is a free service that checks every website address your computer is trying to access, whether you're browsing the internet, clicking a link in an email, or a program "under the hood" trying to communicate with servers for information or updates.
ClearCloud prevents you from being able to access known bad websites, sites that will download malicious files to your computer. Even better, ClearCloud prevents you from being able to access malicious websites that you may not even know your computer is trying to access — and it prevents potentially nasty programs from "phoning home" and secretly communicating between your computer and cybercriminals."
This has the same list as VIPRE Premium's web filter .
Primary DNS server: 188.8.131.52
Secondary DNS server: 184.108.40.206
Its best to put the settings into the router so they are used by all computers connecting to it.
Another alternate to this is Norton DNS: http://nortondns.com/
but I have found Clear Cloud to block more bad sites.