[Exim] error_message problem

Hi there,


Actually I run exim on 2 smarthosts, which relays 2 MX and to
mailhubs.

The problem is when we get dictionnary-spammed, many error messages
are sent to the spamer on a domain which does no necessary exists.

I add a router (close to one found in the FAQ) to drop those domains:

bogus_domains:
driver = domainlist
domains = partial-dbm;/etc/exim/dont-relay.dbm
transport = black_hole
route_list = * localhost byname

black_hole drops message to /dev/null (I'd better use a finish or a
seen command)

Then it works fine. Now the spool does not grow as fast as before and
this release load on the smarthosts.


I was wondering if I can add a condition (such as error_message) to
prevent from dropping mail (which is not and error message) sent to
those domains. This is a rule I can put on a system wild filter:

if error_message and
${lookup{$domain}patial-dbm{/etc/exim/dont-relay}{1}{0}} is "1"
then
seen finish

TIA

PS How do I generate and error message for testing purposes?
For normal messaes, I use:
        exim -bt -d 11 local_part@???

--
Sebastien J. Gross