[COLUG] Exim4 Recipient Whitelisting

[Rick Troth]

This is exactly the kind of thing I want to do,
but either using SENDMAIL or Postfix.  I just don't know
how to wire-in my whitelist checker.  As it is,  it only runs
from  'fetchmail'  which means there is no blowback,  only waste
of my paid-for bandwidth.  [sigh]

Thoughts?

-- R;

On Sat, 22 Sep 2007, Dave Maxwell wrote:

> I have an Exim4 instance in front of an Exchange 2000 server acting as a
> ClamAV/SpamAssassin filter.  Exchange 2000 does a very very braindead thing
> with non-existent users.  It will quietly accept the mail then mail a bounce
> to the From: an hour or two later. This makes deliberate use of blowback for
> spam bouncing trivially easy. Doing a callout/verify on the Exim4 side
> doesn't work as Exchange will vouch for any To: that has
> @exchange_servers_domain.com.  Exchange 2000 simply doesn't have the ability
> terminate at SMTP receive time mails to non-existant recipients.
>
> What I need to do is simply give Exim4 a list of valid recipients.  I could
> then reject mails to non-existent recipients at SMTP connection time.  It is
> a small business with low turnover and having small text file on the Exim4
> side of valid recipients is an entirely practical means to deal with this.
>
> I've found many many howtos on Sender verification and almost everything I've
> found on recipient verification assumes a callout to the smarthost works
> correctly.
>
> The only other way I've found to do it is to make Exim4 query Active Directory
> over LDAP to test recipient validity.  If I have no choice, I'll do it that
> way but I'd prefer something less 'brittle'.
>
> Thanks
>
> Dave
>
> --
> Oh yeah.  Forgot about those.  Getting senile, I guess...
> 		-- Larry Wall in <199710261551.HAA17791 at wall.org>
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