taboo_header confusion

[atta dubson <dubson @ 5-ht . com>]

i need to set up my mailing list to refuse posts if they contain a
certain word anywhere in the headers, including the subject.
if the word is in the body, it is okay for the mail to pass to the
list. however, i am clueless on how to set up the taboo_header.
will anyone please help me? also, will it be case sensative?
and will majordomo just bounce the mail to the owner of the list, or
will it / can it just refuse the post and inform the sender?
thank you. that's all.

-atta