Stavros Tsolakos:
> Hi list.
>
> I am really new to postfix and email-under-the-hood in general.
>
> I have written a milter which in some cases DISCARDs the message, so
> that it may not be sent at all. Is there a way of making postfix notify
> the sender that their email was discarded?
Yes, it is called REJECT.
> I have tried REJECTing it, however sending just failed without further
> explanation for the user, although the reason appeared fine in the log
> file. To avoid client specific issues, I would need something similar to
> the undeliverable mail notifications emails sent to the sender's mailbox.
At which SMTP protocol stage are you issuing the REJECT response?
Try rejecting at end-of-data.
Wietse
