On Mon, Jan 01, 2001 at 08:47:39PM -0500, Greg Owen wrote:
> > I have this problem that when Qmail tried to deliver a
> > message and have this
> > error:
> >
> > Connected to 152.x.x.x but greeting failed.
> > Remote host said: 521 VHAISHEXCI.x.x.gov access denied
> > I'm not going to try again; this message has been in the
> > queue too long.
> >
> ...
> >
> > I expected Qmail to then attempt delivery to the next
> > priority MX. It doesn't and eventually sends me a message
>
> Qmail only backs off to the next MX if it is unable to reach the
> first MX. In this case, it reached the first MX, started a conversation
> with the SMTP server there, and was told to bugger off.
>
> I don't agree with qmail's handling of this case, but it is arguably
> fully legal. I think the standard response here runs "If their mail server
> isn't willing to accept email, why is it responding to port 25?"
I agree with Greg on the latter point, but not the former. As he says,
if the first preference MX says "bugger off" who is more authoritative
than that?
We all know that secondary MX systems tend to know much less about the
domain than the primary does. Consequently a secondary MX *is* likely
to accept such mail, but largely because it has no clue about what the
ultimate destinate thinks.
I recall that this technique is meant to be an anti-spam measure. Can
someone remind me as to how it works and how effective it is - because
the real benefit escapes me?
Regards.
