On Thu, 04 May 2000 17:54:44 CDT, Adam Bailey <[log in to unmask]>  said:
> Well, I can specifically reiterate my long-standing request for
> header-based filtering capabilities in LISTSERV...  :)

Sendmail can do this for you already.

http://www.sendmail.com/blockmelissa.html

The concept is, of course, extensible to other than the
Subject: tag, and there's a whole section in the Sendmail 8.10.1
'cf/README' file labelled 'Header Checks' (down around line 1900).

                                Valdis Kletnieks
                                Operating Systems Analyst
                                Virginia Tech