OT? /dev/null 5.1.1 email

Tony Finch dot at dotat.at
Wed Jul 6 10:20:52 UTC 2005


On Wed, 6 Jul 2005, Pekka Savola wrote:
> On Tue, 5 Jul 2005, Adi Linden wrote:
> >
> > Make your secondary mx aware of all the valid recipient addresses.
>
> Are there mechanisms in postfix or sendmail to do this automatically, or
> should this be done out-of-band?  I've tried looking for this feature, but
> found nothing; maybe I don't know the right terms to search for.

Exim supports call-forward recipient verification, using syntax like
"require verify = recipient/callout". This is very useful if you have any
kind of organizational complexity in your email system which makes it hard
for an MX to know which local parts are valid in all of its domains.

For example, my MXs relay email to about 50 departmental email servers and
act as a secondary MX for some other domains. We have no special knowledge
of which addresses are valid in these domains, and it would be hard to
make that possible because of the variety of software running on the
departmental email servers. However if they are run well such that they
completely verify their recipient addresses during the SMTP conversation,
then so can we.

Tony.
-- 
f.a.n.finch  <dot at dotat.at>  http://dotat.at/
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