Re: [exim] DNS list lookup defer (probably timeout)

On Mon, 2007-05-14 at 11:26 +0200, Renaud Allard wrote:
> Kjetil Torgrim Homme wrote:
> > it is wrong to block bounces to multiple recipients, since it can
> > happen. see the archive for some scenarios.
>
> Well, it's quite OT here, but I consulted the archives, and I still
> can't see any reason why a bounce would be sent to multiple recipients
> at "RCPT TO:" time.

okay, here you go:

system A: your system, accounts alice and bob.
system B: hosts a mailing list administered by alice and bob
system C: hosts charlie which is member of the mailing list

if both Alice and Bob are administrators for the mailing list, they may
receive a bounce from the mailing list host when mail to charlie bounces
(full quota, left company, etc).

since it's the same bounce, system B is allowed to send the two copies
of the bounce in the same transaction to system A.

notice your system can not know if any of your users take part in such a
setup.

(some mailing lists systems will change the envelope sender so the
bounce is no longer a bounce when sent to administrators, but this has
its own problems.)
--
Kjetil T.