无缘无故收到大量退信

lloveher

这几天经常收到类似以下的退信，都好像是有人利用我公司某一邮箱往处发送广告，后被其它邮件服务器做为垃圾邮件拒绝退回，样本如下，版主帮忙看看是不是有人在盗用？我该如何防止这种事件呢？谢谢
其中aa@abc.cn为我们的某一邮箱

Hi. This is the qmail-send program at 9speed.com.
I'm afraid I wasn't able to deliver your message to the following addresses.
This is a permanent error; I've given up. Sorry it didn't work out.

<xianxia@pacific.sh.cn>:
User is over quota email returned
bounce

--- Below this line is a copy of the message.

Return-Path: <aa@abc.cn>
Received: (qmail 64705 invoked by uid 100); 12 Jul 2006 16:26:22 -0000
Received: from aa@abc.cn by ns2.ourwise.com by uid 82 with qmail-scanner-1.21
(uvscan: v4.4.00/v4804.  Clear:RC:0(59.39.229.51):.
Processed in 0.390978 secs); 12 Jul 2006 16:26:22 -0000
Received: from unknown (HELO zovy.cn) (59.39.229.51)
  by localhost with SMTP; 12 Jul 2006 16:26:21 -0000
From: =?GB2312?B?yOe6zrvxyKG6o83i08XWyr/Nu6fT67aptaU=?= <aa@abc.cn>
Subject: =?GB2312?B?yOe6zrvxyKG6o83i08XWyr/Nu6fT67aptaU=?=
To: xianxia@pacific.sh.cn
Content-Type: text/plain;charset="GB2312"
Date: Sun, 16 Jul 2006 05:49:17 +0800
X-Priority: 2
X-Mailer: FoxMail 4.0 beta 2 [cn]
X-Qmail-Scanner-1.21: added fake MIME-Version header
MIME-Version: 1.0
X-Qmail-Scanner-Message-ID: <115272158166164696@ns2.ourwise.com>

|您好！
|
|非常荣幸和您邮件交流!
以下为广告内容

[ 本帖最后由 lloveher 于 2006-7-13 08:45 编辑 ]

clark-down

发送认证啊

asionliang

详看精华。MD安全设置