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Re: How common is lack of DNS server diversity?

  • From: Greg A. Woods
  • Date: Sat Jan 27 17:43:53 2001

[ On Saturday, January 27, 2001 at 01:08:38 (-0800), [email protected] wrote: ]
> Subject: Re: How common is lack of DNS server diversity?
> Thomas Kernen wrote:
> > 
> > And what happens if the route is flapped from the
> > routing table? No more DNS. So you still want route diversity
> > that isn't in the same block or aggregated block.
> You know, some folks simply decide that, for the cost and complexity of
> managing a box in someone else's space (not to mention potential security
> issues, et al, for some) that the loss of DNS server is fairly irrelevant
> if the entire rest of their netblock is offline.

Well maybe, but, it depends on what your offered services are too.

If you're offering e-mail and you've published your addresses as
<[email protected]> but you've got no DNS to hand MX records
back then there's a good chance that many improperly implemented mailers,
and/or DNS resolver libraries that those mailers might use, will bounce
any of your e-mail instead of keeping it in their queues and retrying at
regular intervals.  Whether this is worse than just being off the air
temporarily or not depends on many factors.

Of course if you're doing DNS for many zones then, as others have
already pointed out, having all the nameservers routing into one AS is
definitely going to be less reliable than some of your users might think
it should be.

							Greg A. Woods

+1 416 218-0098      VE3TCP      <[email protected]>      <robohack!woods>
Planix, Inc. <[email protected]>; Secrets of the Weird <[email protected]>