"To:" not matching envelope recipient

[carnold]

I would like to know how to stop this using zimbra. Using OSS 6.0.1 on SLES10.
Here is
a copy of the headers (with specific stuff changed or cut out):

Return-Path: negro2078@hotmail.com
Received: from mail.server.com (LHLO mail.server.com)
(ip.of.server) by mail.server.com with LMTP; Fri, 6 Nov 2009
17:20:34 -0500 (EST)
Received: from localhost (localhost [127.0.0.1])
by mail.server.com (Postfix) with ESMTP id D732ABFF51
for <myemail@mail.server.com>; Fri, 6 Nov 2009 17:20:33 -0500 (EST)
X-Virus-Scanned: amavisd-new at mail.server.com
X-Spam-Flag: NO
X-Spam-Score: 2.346
X-Spam-Level: **
X-Spam-Status: No, score=2.346 tagged_above=-10 required=6.6
tests=[BAYES_05=-1.11, HTML_MESSAGE=0.001, URIBL_BLACK=1.955,
URIBL_OB_SURBL=1.5] autolearn=no
Received: from mail.server.com ([127.0.0.1])
by localhost ( mail.server.com [127.0.0.1]) (amavisd-new, port 10024)
with ESMTP id WTkUevQdagxY for <myemail@mail.server.com>;
Fri, 6 Nov 2009 17:20:29 -0500 (EST)
Received: from cdptpa-imtalb.mail.rr.com (cdptpa-imtalb.mail.rr.com
[75.180.132.34])
by mail.server.com (Postfix) with ESMTP id ED71CBFE1E
for <myemail@mail.server.com>; Fri, 6 Nov 2009 17:20:28 -0500 (EST)
Received: from cdptpa-mxlb.mail.rr.com ([10.127.255.82])
by cdptpa-imta07.mail.rr.com with ESMTP
id <20091106222028261.ETSN29511@cdptpa-imta07.mail.rr.com>
for <myemail@mail.server.com>; Fri, 6 Nov 2009 22:20:28 +0000
[snip..]
X-Originating-IP: [113.66.28.156]
From: =?iso-8859-1?B?QU5UT05JTyBKT1PJIGZsb3JlcyBjYXJtb25h?=
<negro2078@hotmail.com> To: <carnold@braham.k12.mn.us>
Subject: RE # Business
Date: Fri, 6 Nov 2009 22:20:25 +0000

You will notice that "To: <carnold@braham.k12.mn.us>" does not match <myemail@mail.server.com>. Is there anyway to stop this at the MTA level?

[bdial]

not sure you'd really want to stop this. most mailing lists have the to: as the list address not your e-mail address, and it would stop other htings like if someone e-mails another person and cc or bccs you