一直用yum update进行系统升级，现在cetos5.4，结果收不到外网邮件了，退信提示：

This is an automatically generated Delivery Status Notification.

THIS IS A WARNING MESSAGE ONLY.

YOU DO NOT NEED TO RESEND YOUR MESSAGE.

Delivery to the following recipients has been delayed.

       www@sskil.com

请问这是什么原因呀？

1、hotmail、live.cn，邮箱，我碰到的问题，查看日志是如下提示
<liuzwei_cn@hotmail.com>: host mx1.hotmail.com[65.55.37.88] said: 550 DY-001
    Mail rejected by Windows Live Hotmail for policy reasons. We generally do
    not accept email from dynamic IP's as they are not typically used to
    deliver unauthenticated SMTP e-mail to an Internet mail server.
    http://www.spamhaus.org maintains lists of dynamic and residential IP
    addresses. If you are not an email/network admin please contact your
    E-mail/Internet Service Provider for help. Email/network admins, please
    visit http://postmaster.live.com for email delivery information and support
    (in reply to MAIL FROM command)
登录http://www.spamhaus.org/lookup.lasso，将服务器的外网IP地址输入到输入框中，查看IP地址有没有出现在SBL.PBL,XBL中，我的那个IP出现在了PBL中，就按照网站的提示申请删除这个记录，总共两步，第一步是登记一个自设邮件系统的邮件地址，这个网站会发一个5位的确认码，第二步是将这个5位的确认码输到第二步的输入框中，确定后就将我的PBL记录删除了，过一段时间我发信给hotmail、live.cn，就都正常发送了
2、关于SPF，我用这个网站提供的向导做了一个spf记录
http://www.microsoft.com/mscorp/safety/ … fault.aspx
当时选择了ptr，后来收到hotmail的邮件说建议不要采用ptr，我就和中企动力联系将于ptr有关的几个做了删除
3、sina邮箱，我碰到的问题，查看日志是如下提示
<liuzwei_cn@sina.com>: host freemx1.sinamail.sina.com.cn[202.108.3.242] said:
    550 Rejected due to the sending MTA's poor reputation. Please refer
    http://mail.sina.com.cn/help2/rwmail.html (in reply to RCPT TO command)
后来看了本站网友bottle的帖子（http://www.iredmail.org/bbs/thread-970-1-1.html）
去网站http://mipassoc.org/mailman/listinfo/dkim-ops做了一个登记
主要是在Subscribing to dkim-ops登记了一下我的内部邮箱的地址，这个网站会发一个邮件给登记的邮箱一个确认信，进入确认信提供的地址，有一个表格，是一些选项，大家仔细看看，我记不清修改了那些，然后sina的邮箱也好了

sina邮箱的问题我给他们发过邮件，回复是“根据您提供IP，我方查询确认没有针对此IP进行特殊限制，可以正常通信。”，所以我想应该是dkim的问题。

[size=4]以上说的这些可能会有和大家不一样的，请仔细看看每个网站的说明来操作[/size]

希望对大家能够有用。

[ 本帖最后由 liuzwei 于 2009-7-20 15:34 编辑 ]

这是退信的内容
This is the mail system at host mail.sskil.com.

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

<liuzwei_cn@hotmail.com>: host mx1.hotmail.com[65.55.37.88] said: 550 DY-001
    Mail rejected by Windows Live Hotmail for policy reasons. We generally do
    not accept email from dynamic IP's as they are not typically used to
    deliver unauthenticated SMTP e-mail to an Internet mail server.
    http://www.spamhaus.org maintains lists of dynamic and residential IP
    addresses. If you are not an email/network admin please contact your
    E-mail/Internet Service Provider for help. Email/network admins, please
    visit http://postmaster.live.com for email delivery information and support
    (in reply to MAIL FROM command)

<liuzwei_cn@sina.com>: host freemx1.sinamail.sina.com.cn[202.108.3.242] said:
    550 Rejected due to the sending MTA's poor reputation. Please refer
    http://mail.sina.com.cn/help2/rwmail.html (in reply to RCPT TO command)

Reporting-MTA: dns; mail.sskil.com
X-iRedMail-Queue-ID: 52AD013090F
X-iRedMail-Sender: rfc822; www@sskil.com
Arrival-Date: Thu, 16 Jul 2009 17:46:56 +0800 (CST)

Final-Recipient: rfc822; liuzwei_cn@hotmail.com
Original-Recipient: rfc822;liuzwei_cn@hotmail.com
Action: failed
Status: 5.0.0
Remote-MTA: dns; mx1.hotmail.com
Diagnostic-Code: smtp; 550 DY-001 Mail rejected by Windows Live Hotmail for
    policy reasons. We generally do not accept email from dynamic IP's as they
    are not typically used to deliver unauthenticated SMTP e-mail to an
    Internet mail server. http://www.spamhaus.org maintains lists of dynamic
    and residential IP addresses. If you are not an email/network admin please
    contact your E-mail/Internet Service Provider for help. Email/network
    admins, please visit http://postmaster.live.com for email delivery
    information and support

Final-Recipient: rfc822; liuzwei_cn@sina.com
Original-Recipient: rfc822;liuzwei_cn@sina.com
Action: failed
Status: 5.0.0
Remote-MTA: dns; freemx1.sinamail.sina.com.cn
Diagnostic-Code: smtp; 550 Rejected due to the sending MTA's poor reputation.
    Please refer http://mail.sina.com.cn/help2/rwmail.html
这是我的spf记录
[root@mail postfix]# dig -t txt mail.sskil.com

; <<>> DiG 9.3.4-P1 <<>> -t txt mail.sskil.com
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 9266
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2

;; QUESTION SECTION:
;mail.sskil.com.                        IN      TXT

;; ANSWER SECTION:
mail.sskil.com.         1257    IN      TXT     "v=spf1 a ~all"

;; AUTHORITY SECTION:
sskil.com.              99258   IN      NS      ns3.china-enterprise.com.
sskil.com.              99258   IN      NS      ns4.china-enterprise.com.

;; ADDITIONAL SECTION:
ns3.china-enterprise.com. 1243  IN      A       210.51.171.200
ns4.china-enterprise.com. 106585 IN     A       210.51.171.201

;; Query time: 27 msec
;; SERVER: 202.102.134.68#53(202.102.134.68)
;; WHEN: Thu Jul 16 17:49:46 2009
;; MSG SIZE  rcvd: 143
我的邮件系统的是通过路由器映射到内网的一个服务器上的，我公司的域名是由中企动力帮助解析的，可以通过域名访问我的邮件系统，上面的spf记录是通过http://www.xiaohui.com/dev/server/email … config.htm地址来生成的

请看看是否正确，不正确的话应该怎样设定

现在给gmail发邮件没有问题

今天设置好邮件服务器（主机名：mail.company.com）后，可以收发内部网络的邮件，可以将邮件发送给外部的邮箱，为了实现能够收到外网邮件，就请给我公司做网站的公司（中企动力）帮助解析邮件服务器的名字，对方向我要mx记录，什么是mx记录？如何获得呢？

[ 本帖最后由 liuzwei 于 2009-7-13 16:38 编辑 ]