I have a list where we do that in the [listname].mailtpl file.  There is a
section with the header >>> CONTENT_FILTER where you can specify text strings
in either the subject, the header, or the text of the message to block incoming
mail.

The online listserv manual specifies it as a technique for dealing with out of
office messages, i.e.,

>>> CONTENT_FILTER
Subject: Out of Office
Action: DISCARD
Subject: Out of the Office
Action: DISCARD

The manual explicitly states that the content filter is not a spam filter. See
http://www.lsoft.com/manuals/1.8e/owner/owner.html#_Toc9154203

Good luck!

Dennis Gormley

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Original message(s) follow:



>Is there any way to filter messages according to keywords in subject line,
>instead of filtering according to sender's address?

>Thanks!

>- Ming