How common is lack of DNS server diversity?

Mon Feb 5 22:29:10 UTC 2001

> > Then it probably doesn't matter if you resolve their DNS,
> > because you won't be getting to any of their services anyway.
>
> Several folks have mentioned that they don't see a problem with
> dns failure caused by an inability to reach all of the
> nameservers for a domain - because presumably clients won't be
> able to reach any of the hosts in that domain.

That's a wrong justification, not only due to the reasons you go on
to cite, but because detecting a failure to look up a name takes a
rather long time (your name server or resolver will typically have
to rely on a time-out), while reacting to an ICMP Host Unreachable
as a response to a TCP connection attempt is pretty quick (if your
network is indeed off the net, but your DNS service isn't).

This probably makes for easier debugging / better user reports, less
of a "world wide wait", faster mailing list deliveries and probably
also has other beneficial effects.

Regards,

- Håvard