Unfortunately, despite the anycasting, advanced caching, and extensive security features, Google Public DNS is not the ideal DNS service. For one thing, it's not called “experimental” for nothing. From my home, I can’t reach 18.104.22.168. Packets end up ping-ponging between the addresses 22.214.171.124 and 126.96.36.199. Apparently some routing engineer at Google is a bit dyslexic.