How do I bar e-mail (SPAM) to certain domains

[Stefaans]

One of our clients has hundreds of parked domains and these domains are attracting tons of SPAM, eating up expensive bandwidth. The client is happy that we block all e-mail to these domains.

What should I do to NOT accept e-mail for these domains? I do not want to :fail: or :blackhole:. I rather want to stop the e-mail at its origin before it even gets onto the server.

I have tried the following with one of the domains:
* Removed it from /etc/localhosts. Mail still enteres the server and is bounced. Not good enough.
* Changed the domain's zone MX entry to 127.0.0.1. Mail is rejected without entering the server. This is the desired result, but is it acceptable practice?

Could I not set up something in /etc/exim.conf, e.g. some kind of "blacklist"?

Thanks for your comments

[bennet]

If you have installed MailScanner, see:
http://forums.cpanel.net/showthread....ight=blacklist