[Mailman-Users] Filtering Reply to list with informative rejection message

[Stephen J. Turnbull]

francis picabia writes:

 > We have experienced a case where nominations were solicited from
 > the list members, and there was a response with confidential
 > information which went to the list rather than the poster.

There is no way to have an unmoderated list which prevents
"confidential" information from going to the list.  The only way to
prevent certain information from going to the list is to restrict
posting to those who don't have the information.  (This is why secret
organizations use "cell" organization.  You can't reveal what you
don't know.)

 > There is a possibility management will want to block all replys to
 > the mailing list.  One could work around it by making a fresh email
 > to the list.

The requirement is not clear.  Does management want to block such
fresh emails as well?  Or is the idea that fresh emails be the
ordinary way to reply to list, hoping that people will be reminded not
to post confidential information?

 > The Spam Filter rule to Reject based on finding "^In-Reply-To:" works well,
 > but the simple rejection is not going to be understood by our users:
 > 
 > Message rejected by filter rule match

Systems based on rejecting user input do *not* work well in the long
run in my experience.  Users get annoyed and avoid doing work they
*should* do, or develop (inefficient) habits that result in
unintended posts anyway.

 > Is there another option I have not covered or I have misunderstood
 > something here?

The other option is to put the responsibility on the individuals
soliciting confidential information.  Create a fully personalized list
with Reply-To set to the mailbox intended to receive confidential
information.  If the senders themselves are typically not authorized
to see the information, create a separate mailbox (account) for use by
those authorized to solicit confidential information.

I can't be sure that any of the above addresses your (or your
management's) needs.  But without a better idea of what they're trying
to accomplish and why, it's hard give good advice.