In response to "Leonardo Boselli":
> I would like to put something that for every message addressd to
> user@??? would both deleiver the message and send both to
> the user AND to the sender a short message stationg that all
> addresses of the form user@??? had become user@???
For the message to the sender, an autoreply transport invoked by an
unseen smartuser director with domains = a.g.c.d . For the message to
the recipient, I would suggest off the top of my head a pipe transport
invoked by an unseen smartuser director with domains = a.g.c.d to pipe
the message (or only the headers in fact) to a script that picks out
the To: field and generates the message. In both cases the director
needs to have senders = ! exim@??? or similar, to stop the message
to the user generating two more messages. The directors need to be
unseen and near the start of the set of directors so that the message
falls through to whatever is actually going to deliver it.
