Russell Nelson <[EMAIL PROTECTED]> writes on 27 September 1999 at 17:27:30 -0400
> David Dyer-Bennet writes:
> > Russell Nelson <[EMAIL PROTECTED]> writes on 27 September 1999 at 16:44:19 -0400
> > > > 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".
>
> Right, but you're suggesting that nobody will notice the lack of
> reception of email for seven days. If they make configuration changes
> without testing them (and I count leaving a down machine down as
> such), and then don't notice that something is broken for a week, then
> I'll wager that they'll be suited just as well without email.
They will continue to receive email, as I understand it, except from
qmail sites. So they won't see an obvious symptom such as "no email
arriving".
> You're also presuming that they have the ability to read email off the
> "secondary" host. It would be very unusual for a host which functions
> identically to another to be given a lower priority. Much more often,
> the secondary host is one which is configured only to relay mail to
> the primary.
I'm presuming that the primary and secondaries are boundary hosts that
feed into some internal pool of systems for mail handlings. This is
not uncommon at larger sites, but by no means universal either.
> > > 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!
>
> And a firewall which accepts connections for a down host is not
> misconfigured or broken by design??
I'd agree that it is, in fact, misconfigured or broken. I also
believe it's a very easy mistake to make, since the mail hosts will
presumably not be down all that often.
--
David Dyer-Bennet ***NOTE ADDRESS CHANGES*** [EMAIL PROTECTED]
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