[ On Saturday, January 27, 2001 at 01:08:38 (-0800), lucifer@lightbearer.com wrote: ]
Subject: Re: How common is lack of DNS server diversity?
Thomas Kernen wrote:
And what happens if the 4.0.0.0/8 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 <user@subdomain.yourdomain.tld> 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 <gwoods@acm.org> <robohack!woods> Planix, Inc. <woods@planix.com>; Secrets of the Weird <woods@weird.com>