[dns-operations] Google DNS used as amplification - aren't they caching?

[Lutz Donnerhacke]

* Paul Wouters wrote:
> It seems that the nsd ratelimits to send TC=1 isn't working well either
> to reduce the incoming amount of UDP queries.
>
> Why does google dns seems so inefficient at caching?

I can second this. With rate limiting and dampening (at my side) I get
customer complains, that the Google webmaster tools report an unreachability
of the DNS servers (about 5%).

OTOH there are customers which use Google public DNS and do have sporadic
resolving problems "Internet is not working! We can't even access our own
home page!"

And this is true: Google IP ranges hit the dampening limits several times
the day.