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Date: Thu, 29 Sep 2005 15:46:06 -0400 (EDT) From: Todd Vierling <tv@duh.org> To: Randy Bush <randy@psg.com> Cc: Matthew Crocker <matthew@crocker.com>, "Robert E.Seastrom" <rs@seastrom.com>, nanog@nanog.org In-Reply-To: <17212.12082.163714.143619@roam.psg.com> Errors-To: owner-nanog@merit.edu On Thu, 29 Sep 2005, Randy Bush wrote: > >> You might want to consider reading RFC 2182 though, particularly the > >> part about geographically diverse nameservers. > > Yeah, yeah, that is overrated. If my site goes dark and my DNS goes > > down it doesn't really matter as the bandwidth and the web server > > will also be down. > > and folk who would otherwise spool mail for you will throw it > on the floor. enjoy. As I tried to explain in the other response, if this were the case with said unnamed MTAs, then a simple tier-1 outage (which is not all that uncommon) or a site under packet flood attacks would cause immediate bounces due to DNS timeouts. The same thing applies to a site whose DNS is simply unreachable because its link is down. When a MTA gets a failed lookup response, it should retry. When the domain *does* resolve, but resolves to *empty or nonexistent*, then the mail should bounce. When a DNS server is unreachable, it can hardly return a NXDOMAIN back to the requestor. 8-P -- -- Todd Vierling <tv@duh.org> <tv@pobox.com> <todd@vierling.name>
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