Robert Schetterer:
> > Nobody said that the fallback relay has to another machine. You
> > can and should in many cases configure a second Postfix instance
> > on each machine to be the fallback relay, this solves the greylisting
> > by IP problem, and keeps the fallback load distributed to all the
> > available hardware.
> >
> > In the fallback queue (instance) increase the active queue limits,
> > and delivery agent process limits, since you expect this mail to
> > generate less network traffic per delivery attempt and to incur
> > a larger active queue size due to the longer queue occupancy per
> > message.
> >
> > There is no need to redesign Postfix, in fact getting the junk out
> > of the primary queue is always preferable.
> >
>
> what about fallback relay being a loadbalancer ip , with logic included
> forward by i.e fifty fifty percent balance to other i.e two other
> postfix servers ? This should goal too, and leaves the first server
> power free
> for new jobs
The issue is not computer power. The issue is that a fall-back MTA
requires a fundamentally different configuration (*). One benefit
of running the fall-back on the same host is that this reuses the
sender IP address, and thereby speeds up IP-based whitelisting
(greylist, postscreen).
Wietse
(*) To begin with, one has short timeouts for quick delivery, and
one has long timeouts to push out mail to problematic destinations.
