[Exim] Delivering mail for users with no account

Hello,

I’m trying to get Exim to deliver all mail for which there is no local
account for to a single account. The way I’ve thought of to do this (and
perhaps this is way off the mark) is by having a director that catches
addresses not picked up on by other directors. My new director would
then pass the message to an appropriate transport for my catch-all
account. I also need the destination addresses of the messages to be
preserved so that my catch-all accounts messages can be downloaded to
another MTA which will sort out the messages based on their original
addresses.

I tried putting a director at the end of the list with no driver but
Exim didn't like this. I’m a little confused about the whole concept of
the driver to be honest. Presumably the driver is the actual condition
that causes the address to be caught and “directed” but how would I go
about writing one myself? Or are they all simply “built it”? The
documentation describes drivers as a collection of directors, routers,
and transports, which confused me all the more!

Any help would be greatly appreciated!

Andy