向一些企业邮箱发送的邮件被退回。请高手帮忙分析解决一下。
退回邮件如下：（地址已被替换）
-----Original Message-----
From: Mail Delivery System [mailto:MAILER-DAEMON@xxx.xxxxx.org]
Sent: Thursday, June 25, 2009 12:38 PM
To: aaa@aaaaa.com
Subject: Undelivered Mail Returned to Sender

This is the mail system at host xxx.xxxxx.org.

I'm sorry to have to inform you that your message could not be delivered to
one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can delete your own
text from the attached returned message.

                   The mail system

<aaa@aaaaa.com>: host mail2.aaaaa.com[191.11.222.22] said:
550
    Rule imposed as abc@abc.asia is believed to be an open relay (in
    reply to RCPT TO command)
Reporting-MTA: dns; xxx.xxxxx.org
X-iRedMail-Queue-ID: C1A1F9387A9
X-iRedMail-Sender: rfc822; abc@abc.asia
Arrival-Date: Thu, 25 Jun 2009 12:06:57 +0800 (CST)

Final-Recipient: rfc822; aaa@aaaaa.com
Original-Recipient: rfc822;aaa@aaaaa.com
Action: failed
Status: 5.0.0
Remote-MTA: dns; mail2.aaaaa.com
Diagnostic-Code: smtp; 550 Rule imposed as abc@abc.asia is believed to
    be an open relay

[ 本帖最后由 tjyzhy 于 2009-6-25 21:25 编辑 ]