exchange2003群集系统不能收邮件问题

june

exchange2003群集系统，在PIX防火墙内部，内部收发正常，能发邮件，不能收邮件,mx记录正常。263发给这个邮箱的退信如下：<br>
<br>
This is the Postfix program at host smtp.263.net.<br>
<br>
I'm sorry to have to inform you that the message returned<br>
below could not be delivered to one or more destinations.<br>
<br>
For further assistance, please send mail to <postmaster><br>
<br>
If you do so, please include this problem report. You can<br>
delete your own text from the message returned below.<br>
<br>
The Postfix program<br>
<br>
<test1@xxx.com.cn>: connect to mail.xxx.com.cn[220.167.xxx.xxx]:<br>No route to host<br>
<br>
请问什么原因？

june

哪位能支持一下？