Russell Nelson <[EMAIL PROTECTED]> writes on 27 September 1999 at 16:44:19 -0400
> David Dyer-Bennet writes:
> > What is the appropriate MTA behavior in this case? It seems clear
> > to me that what everybody would want in this situation is for an
> > MTA to fail over to the secondary MX.
>
> If their MX records are incorrectly configured, their email isn't
> going to go through. Why should other hosts go through heroic hoops
> just to get the mail to them?
I would not describe the MX records as incorrectly configured; the
primary MX points to what's supposed to be their primary mail
exchanger, *but it's down for an unexpectedly long period*. Since
they have a secondary MX in place, they don't worry about updating the
DNS, expecting MTAs to fail over to the secondary DNS since the
primary is down.
Nor do I consider it jumping through "heroic hoops" to notice that you
can't connect to the primary MX, and decide to try the next one.
> > Should we be giving any consideration to the question of whether, on
> > the average, secondary MXs are less reliable than primary? I don't
> > think we should; I don't think we should warp the implementation to
> > accommodate incorrectly configured systems.
>
> Aren't you doing just that? Right now, qmail works fine for machines
> which are correctly configured but sometimes inaccessible.
It doesn't work fine in the scenario I outlined at the beginning of my
message. In that situation, the mail will sit on the qmail system
until it expires, when there's a perfectly good secondary MX system
sitting there waiting to accept it. This is not my definition of
"works fine".
> Various people (not you) are talking about warping the
> implementation to accommodate incorrectly configured systems.
> There's a ton of different ways you can configure your system so
> that email bounces. Why should a remote system bother to work
> around any of them? I mean, there's the chance that the SMTP
> server might be configured with the wrong hostname, so the client
> should strip off the hostname for the RCPT TO: lines, right??
The secondary MX exists to cover cases when the primary is down. It's
not an "incorrectly configured" DNS to have a primary MX listed that
happens to be down at the moment!
--
David Dyer-Bennet ***NOTE ADDRESS CHANGES*** [EMAIL PROTECTED]
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