[exim] Queueing-issue when greylisted....

Hi all,

I have an annoying problem regarding my mailqueues. Some users forward
all their incoming messages to remote domains which perform greylisting.
The setup is something like "defer the first delivery and accept any
message that ist retried more than 5 minutes and less than 12 hours
after the initial delivery attempt".

For a given recpipient mail arrives frequently, and every incoming
message triggers a delivery-attempt, which often triggers greylisting
which a 451-response-code. However, the retry-interval is recalculated
and messages sitting in the queue are not retried for that recipient, so
a second delivery just never happens and the message is kept in the
queue forever.

Currently I have no better idea than to run a cronjob doing someghing
like "exim -Rff domain" every hour. But I don't really like that
"solution" and though my mail-throughput is small enough and the
hardware has enough spare resources, I'm curious how others try to solve
that issues.

Any comments, ideas, suggestions?

--
CU,
Patrick.