Re: [Exim] MAIL ACL and sender verification

On Wed, 25 Dec 2002, Marc MERLIN wrote:

> At least one very unfortunate byproduct is that when I reject an Emamil
> for bad HELO, or bad mail from at rcpt to time,

Just for clarification - you're talking about issuing the 5xx for
those causes at RCPT TO time, just like I mentioned earlier in the
thread, I'm assuming?

> stupid mailers/MTA
> combos like outlook/exchange will say "user unknown", completely
> ignoring the error message I sent back in 5xx

It appears to be a microsoft speciality, that they are inclined to
discard the real error message and construct some fiction of their own
for presenting to the luckless user. It not only _happens_ in MSIE -
the misbehaviour is even documented (what we used to call DAB =
Documented As Broken, not to be confused with BAD = Broken As
Designed - though they have some of that too).

> Then, those people call me and ask me why _my_ mail doesn't work.

Curiously, in my experience as deputy postmaster for the department,
the most likely user response to any kind of failure to send us a mail
is to try to send it again (maybe several times), to the same address
and with the same cause of failure present, and then to give up.

The number of occasions where, after an apparently bona fide mail has
failed, the sender responds by contacting the postmaster seems to be
surprisingly tiny. Sometimes we hear at third hand that the sender is
disparaging our reputation on the basis of some objective fault in the
mailer or address that _they_ were using - but they rarely offer us
any opportunity to correct their misapprehension. As you say, it is
rather annoying.

But on the other hand, _most_ of the failures of this kind relate to
attempted spams, so I reckon 'the spell is working', on balance.

cheers