mailscanner as a front-end, help!

[Jeff A. Earickson]

Gang,

I slid my legacy MailScanner system back in front of my email
appliance this morning to block spam.  I've got a problem with
non-existent/dictionary attack addresses now.  They get sent
on to the appliance, who doesn't know the address, thence back
to the front-end, unroutable -- mail loop, too many hops.
I need MailScanner/sendmail to kill non-existent addresses up
front.  I found milter-ahead (costs euros).  Any other ideas?
Virtusertables, like http://q.queso.com/archives/002025?

My setup: sendmail 8.14.1, MailScanner 4.62.9, SA and the other
anti-spam additions.  sendmail running as "define(`MAIL_HUB'"
setting to pass all (non-spam) email on to the appliance for
local delivery.

Jeff Earickson
Colby College