8.8.8.8 and 4.2.2.1 have strict rate-limits configured that make them uninteresting/unsuitable for reflection attacks. The real issue is misconfigured resolvers

8.8.8.8 and 4.2.2.1 have strict rate-limits configured that make them uninteresting/unsuitable for reflection attacks. The real issue is misconfigured resolvers exposed to the internet, not intentionally-provided recursive resolvers. If you'd like to have a private DNS server, it's fairly easy to set up your own recursor. (Just please don't expose it to the whole internet.)