如何解决qmail无法向部分服务器发信问题？

lsunx

redhat linux as 3 update 6安装qmail
netmail-1.05
vpopmail-5.4.10
安装好，收发信都一切正常，但唯独对几个域名的mail，如果带附件的话无法成功发送
无法发信的邮箱：
@sbaif.com
@deloitte.com.cn

日志中的错误为
delivery 23031: deferral: Connected_to_64.18.7.10_but_connection_died._Possible_duplicate!_(#4.4.2)/

使用host命令查看显示如下内容
host -t mx sbaif.com
sbaif.com mail is handled by 100 sbaif.com.s8a1.psmtp.com.
sbaif.com mail is handled by 200 sbaif.com.s8a2.psmtp.com.
sbaif.com mail is handled by 300 sbaif.com.s8b1.psmtp.com.
sbaif.com mail is handled by 400 sbaif.com.s8b2.psmtp.com.
sbaif.com mail is handled by 450 mail.sbaif.com.

host -t mx deloitte.com.cn
deloitte.com.cn mail is handled by 200 deloitte.com.cn.s7a2.psmtp.com.
deloitte.com.cn mail is handled by 300 deloitte.com.cn.s7b1.psmtp.com.
deloitte.com.cn mail is handled by 400 deloitte.com.cn.s7b2.psmtp.com.
deloitte.com.cn mail is handled by 600 mailbackup.deloitte.com.hk.
deloitte.com.cn mail is handled by 100 deloitte.com.cn.s7a1.psmtp.com.

TELNET 25端口进行测试如果如下：
telnet mail.sbaif.com 25
Trying 203.98.173.238...
Connected to mail.sbaif.com (203.98.173.23.
Escape character is '^]'.
220 server03.sbaif.com Microsoft ESMTP MAIL Service, Version: 5.0.2195.6713 ready at  Fri, 9 Dec 2005 09:48:47 +0800

telnet 64.18.7.10 25
Trying 64.18.7.10...
Connected to 64.18.7.10 (64.18.7.10).
Escape character is '^]'.
220 Postini ESMTP 7 y6_4_5c0 ready.  CA Business and Professions Code Section 17538.45 forbids use of this system for unsolicited electronic mail advertisements.

网上搜索不到任何这方面的资料，请高手帮忙分析一下可能的原因，及解决之道，谢谢！

大麻

多半是你的服务器 ip 列入了黑名单之列，或者向对方发送邮件太过于频繁等等，原因太多了。

mxli

我的是这样的
500 PSMTP Unimplemented command: Trying 64.18.7.10... - psmtp
500 PSMTP Unimplemented command: Connected to 64.18.7.10 (64.18.7.10). - psmtp
500 PSMTP Unimplemented command: Escape character is '^]'. - psmtp
500 PSMTP Unimplemented command: 220 Postini ESMTP 18 y6_4_5c0 ready.  CA Business and Professions Code Section 17538.45 forbids use of this system for unsolicited electronic mail advertisements. - psmtp
500 PSMTP Unimplemented command: 500 PSMTP Unimplemented command:  - psmtp - psmtp
500 PSMTP Unimplemented command: 500 PSMTP Unimplemented command:  - psmtp - psmtp
500 PSMTP Unimplemented command:  - psmtp
500 PSMTP Unimplemented command: 500 PSMTP Unimplemented com

lsunx

这此公司都是我们的合作伙伴，有频繁的业务往来，经常需要发送一些带doc、xls文档的邮件。
有哪些解决办法吗？

mxli

让他们检查下，还有你的反向解析做了发