How common is lack of DNS server diversity?

Sat Jan 27 11:35:55 UTC 2001

On Sat, 27 Jan 2001, Roeland Meyer wrote:

[snip]
> dot root servers should be spread out, as they are authoritative for
> everything.
> TLD root servers should also be spread out, they are authoritative for many
> things.
> SLD root servers need not be spread out so much, they are authoritative for
> few things.
> 3LD root servers don't need to even leave their AS, if the AS is down the
> servers, they are authoritive for, are probably also down.
> 4LD root servers ... who cares?

ok, these are obviously generalisations and most DNS-savvy folk would
agree with a pinch of salt and a mumble about special cases.

e.g. (in particular) {\8}.in-addr.arpa should be considered a TLD in this
context.

> More interestingly, how many root servers allow recursive lookup?

a quick looping probe shows that none of them do, nor the gTLD servers
(phew!) although L.ROOT-SERVERS.NET and H.GTLD-SERVERS.NET are unreachable
from my view. Preparing an accurate list of all TLD servers glued in the
root zone will take a little longer.

joshua