比较疑惑的垃圾邮件？

mike_zhang0917

钉子兄及各位邮件系统高手，最近我公司的用户老是受到一些一下类似的垃圾邮件，邮件头如下，我很奇怪，该垃圾邮件发件人冒充了我公司真实的收件人地址，公司的邮件服务器配置：Windows 2003 R2+MS Exchange 2003 SP2+TrendMicro Scanmail 7.0，配置了反向DNS查找，公司的邮件服务器也配置了反向DNS解析。

邮件头如下：

Received: from rev-179-19.ramtel.pl ([91.90.179.19]) by mail.medic???.com with Microsoft SMTPSVC(6.0.3790.3959);
  Wed, 17 Oct 2007 05:29:46 +0800
Received: from Cheryl Simon (10.15.15.18) by rev-179-19.ramtel.pl (PowerMTA(TM) v3.2r4) id hfp20o66d73j65 for <[email=laj@medic???.com]laj@medic???.com[/email]>; Tue, 16 Oct 2007 11:27:31 +0100
Message-Id: <20071016122731.20271.qmail@rev-179-19.ramtel.pl>
To: <[email=laj@medic???.com]laj@medic???.com[/email]>
Subject: October 73% OFF
From: VIAGRA ?Official Site <[email=laj@medic???.com]laj@medic???.com[/email]>
MIME-Version: 1.0
Content-Type: text/html; charset="iso-8859-1"
Content-Transfer-Encoding: 8bit
Return-Path: foxbtrkg@medicine.wustl.edu
X-OriginalArrivalTime: 16 Oct 2007 21:29:47.0432 (UTC) FILETIME=[AD290280:01C8103B]
Date: 17 Oct 2007 05:29:47 +0800
X-TM-AS-Product-Ver: SMEX-7.0.0.1557-5.0.1023-15488.001
X-TM-AS-Result: No-36.467900-0.000000-1

最后，高手帮忙解释一下该垃圾邮件的发件人为何和真实的收件人是一样的？请教诸位有没有比较好的方法处理此类垃圾邮件，软硬件的方法或方案。

钉子

要这是都是October 73% OFF的话就关键词过滤吧.