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>