I recall a program/process Procmail at an ISP I used, where one could build
filters to trap messages (SPAM traps) before they were distributed.  Based
on these rules the message would be routed to the proper mail box, often the
garbage.  For HP3000 user that would be the $NULL file!

See this link for a start for Procmail info.
http://www.wolfenet.com/~jhardin/

Lars Appel <[log in to unmask]> wrote in message
news:961sqr0irh@enews1.newsguy.com...
> While I don't play a sendmail expert on TV ;-) I seem to vaguely
> recall that the sendmail aliases file can be used to configure
> "users" that don't receive incoming mail into a file but into a
> "pipe" that feeds the message into a user supplied shell script
> for automated processing.
>