[Mailman-Users] Discard notification problem

[Thomas Hartwig]

I am running some lists with mailman and I have made real good
experience. The problem which occurs now occasionally is that sometimes
messages become discarded silently. The "vette" log contains very small
information once a message is discarded. The discarding seems to happen
preferable with freemailer accounts like web.de or freenet located here
in germany.
My core problem is that the sender (which is subscribed or white listed)
is not notified by the discarding. Ok - this is what discarding means
actually, but I am wondering if there is a possibility to avoid
discarding in general or to get known why it happened. I have
investigated already some time in this issue but I am afraid I am a
little bit confused and lost in the code. So I have following questions:

1. Is there a global option to prefer rejecting over discarding?
2. Is there some kind of extended logging available to see the reasons
of discarding?
3. Is there a global option to get notified by discards?

Thanks
Thomas