From: Wietse Venema (no email)
Date: Thu Nov 01 2007 - 12:25:13 EDT
> On Thu, 1 Nov 2007, Wietse Venema wrote:
> > :
> >> Sure - and I've gone one better and hidden my real MX somewhere between
> >> the rejecting ones at the top (which leads to immediate retries to the
> >> next MX down, which may or may not do the same thing), and the tarpitting
> >> ones at the bottom. And even if a valid MTA gets to the bottom ones
> >> through a minor network outage, it'll still eventually time out and roll
> >> over to retry from the top after a little while.
> > The RFC does not require that an SMTP client tries every MX host.
> > It only requires two. If you list lots of non-responding MX hosts
> > then you can expect interoperability problems.
> Sure - but if the top two were tried in the correct order, this problem
> wouldn't have happened, and if I saw it give up after two, I'd not be
> asking why it started at the 16th and didn't go from there for 5 hours.
What's the TTL in the SOA record for the domain in question?