Victor Duchovni:
> On Thu, Jul 21, 2011 at 10:00:35PM +0200, Jeroen Geilman wrote:
>
> >> It is useful, when you want envelopes with recipient in both domains
> >> to be handled in a single transaction with the target nexthop, rather
> >> than a separate transaction for each domain (default).
> >
> > I understood that part, but that means you'd have to know in advance that
> > that nexthop is prepared to handle both messages.
> > In other words, it's a manual optimization for special cases.
>
> Yes, with internal relay hops for domains under one's own control. This
> seems to be the OP's situation.
The alternative would require what is called MX piggy-backing, where
the MTA looks up the MX records for all the recipients of a message,
and sorts the recipients by the MX IP address (instead of the
next-hop domain name like Postfix does) before starting email
delivery. This would have a major impact on delivery performance
of large mailing lists. And, since qmail did not implement MX
piggy-backing, I thought I could get away without it in Postfix.
Wietse
