[Exim] Discarding messages based on IPs from Received:

The idea is pretty obvious - extract IPs from all Received: headers,
run all of them through check on some dnslist and/or own list and
discard message if any of those IPs giving positive reaction. This is
actually even more advanced method than classical check for incoming
IP on dnslists because it works for relays too. Did anybody played
with such setup?

Actually I've just created one on my system and so far it works well.
I'm using this check in acl_smtp_data ACL as addition to receiver
verification, i.e. it's running only if address is valid. The check
itself is made as a perl function (I've compiled exim with perl
support). I'd prefer to use exim's internal dnslists support, but it
looks like there is no way to do this.

Will appreciate any comments.

Andrey