On Wed, 2009-04-01 at 10:40 +0100, Peter Bowyer wrote:
> 2009/4/1 Tomasz Chmielewski <mangoo@???>:
> >
> > I know the proper way to do it would be to have an up-to-date list of
> > existing users on the Exim box for all "remote users", but it's not
> > always possible.
>
> That's a great use case for Exim's recipient callout verification. As
> long as the destination server rejects unknown recipients at SMTP
> time, your Exim will 'learn' (ie cache) which users are valid and
> which are not and reject invalid users.
>
The problem then (as seen here recently) is that Exim's cache gets out
of step with the recipient server. Exim then accepts the message, but
the recipient server rejects it. A bounce goes back to the sender, which
is what the OP was trying to avoid.
In our case we have reduced the positive cache time, but I see no way
around some window of time existing in which a bounce could be sent out
other than not using Exim's positive cache at all.
John.
--
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John Horne, University of Plymouth, UK Tel: +44 (0)1752 587287
E-mail: John.Horne@??? Fax: +44 (0)1752 587001
