How common is lack of DNS server diversity?

Sat Jan 27 15:58:10 UTC 2001

All:
  I have a related question that may be dated at this point but of which
I'm curious. Some time ago we had a problem with a DNS server we located
on a totally separate network to achieve DNS server diversity. At one
point there was a failure on that network so that our DNS server loacted
there could not be reached. It appeared from the reports/complaints we
received that a number of client systems/resolvers had decided to only
request data from the nonfunctional DNS server and despite failing on that
wouldn't ask our other listed DNS servers. They therefore could not
resolve addresses for otherwise functional network assets. I seem to
remember this was somehow related to systems running Microsoft OS's.
  Am I confused or could it be that Microsoft knows something about this?

Chuck Scott