客户的邮件发不进来。提示“连接关闭”。。附日志。请帮忙瞅瞅。。

ken_tech

Sun 2012-08-26 01:59:11: Accepting SMTP connection from [164.90.7.75:46680]
Sun 2012-08-26 01:59:11: --> 220 ABC.com.cn ESMTP MDaemon 10.1.1; Sun, 26 Aug 2012 01:59:11 +0800
Sun 2012-08-26 01:59:12: <-- EHLO ISQSPAM02.osi-systems.com
Sun 2012-08-26 01:59:12: --> 250-ABC.com.cn Hello ISQSPAM02.osi-systems.com, pleased to meet you
Sun 2012-08-26 01:59:12: --> 250-ETRN
Sun 2012-08-26 01:59:12: --> 250-AUTH=LOGIN
Sun 2012-08-26 01:59:12: --> 250-AUTH LOGIN CRAM-MD5
Sun 2012-08-26 01:59:12: --> 250-8BITMIME
Sun 2012-08-26 01:59:12: --> 250 SIZE
Sun 2012-08-26 01:59:12: <-- MAIL FROM:<Isabel.Donnelly@spacelabs.com> SIZE=104450
Sun 2012-08-26 01:59:12: Performing PTR lookup (75.7.90.164.IN-ADDR.ARPA)
Sun 2012-08-26 01:59:12: *  D=75.7.90.164.IN-ADDR.ARPA TTL=(30) PTR=[mail4.osi-systems.com]
Sun 2012-08-26 01:59:12: *  Gathering A records...
Sun 2012-08-26 01:59:12: *  D=mail4.osi-systems.com TTL=(60) A=[164.90.7.75]
Sun 2012-08-26 01:59:12: ---- End PTR results
Sun 2012-08-26 01:59:12: Performing IP lookup (ISQSPAM02.osi-systems.com)
Sun 2012-08-26 02:00:12: *  DNS: 60 second wait for DNS response exceeded
Sun 2012-08-26 02:00:12: *  Error: *  名称服务器报告未知的域名
Sun 2012-08-26 02:00:12: ---- End IP lookup results
Sun 2012-08-26 02:00:12: Performing IP lookup (spacelabs.com)
Sun 2012-08-26 02:00:12: *  D=spacelabs.com TTL=(60) A=[74.200.224.138]
Sun 2012-08-26 02:00:13: *  P=010 S=000 D=spacelabs.com TTL=(30) MX=[mail3.osi-systems.com]
Sun 2012-08-26 02:00:13: *  P=010 S=001 D=spacelabs.com TTL=(30) MX=[mail4.osi-systems.com] {164.90.7.75}
Sun 2012-08-26 02:00:13: *  P=020 S=002 D=spacelabs.com TTL=(30) MX=[mail1.osi-systems.com]
Sun 2012-08-26 02:00:13: *  P=020 S=003 D=spacelabs.com TTL=(30) MX=[mail2.osi-systems.com]
Sun 2012-08-26 02:00:13: ---- End IP lookup results
Sun 2012-08-26 02:00:13: --> 250 <Isabel.Donnelly@spacelabs.com>, Sender ok
Sun 2012-08-26 02:00:13: 连接关闭
Sun 2012-08-26 02:00:13: SMTP session terminated (Bytes in/out: 87/270)
Sun 2012-08-26 02:00:13: ----------

ken_tech

已经将该客户邮件服务器IP已经添加到反向查询、SPF、DNS-BL白名单中。。

ken_tech

各位大大，有木有人知道是怎么回事呀。。帮忙看看呢。。。

ken_tech

Tue 2012-09-04 09:59:54: Session 8700; child 25; thread 15240
Tue 2012-09-04 09:58:54: Accepting SMTP connection from [XXX.14.XXX.37:44434]
Tue 2012-09-04 09:58:54: --> 220 AAA.com.cn ESMTP MDaemon 10.1.1; Tue, 04 Sep 2012 09:58:54 +0800
Tue 2012-09-04 09:58:54: <-- EHLO corp.21cn.com
Tue 2012-09-04 09:58:54: --> 250-AAA.com.cn Hello corp.21cn.com, pleased to meet you
Tue 2012-09-04 09:58:54: --> 250-ETRN
Tue 2012-09-04 09:58:54: --> 250-AUTH=LOGIN
Tue 2012-09-04 09:58:54: --> 250-AUTH LOGIN CRAM-MD5
Tue 2012-09-04 09:58:54: --> 250-8BITMIME
Tue 2012-09-04 09:58:54: --> 250 SIZE
Tue 2012-09-04 09:58:54: <-- MAIL FROM:<zhouying@BBB.cn> SIZE=2962
Tue 2012-09-04 09:58:54: Performing PTR lookup (37.XXX.14.XXX.IN-ADDR.ARPA)
Tue 2012-09-04 09:58:54: *  D=37.XXX.14.XXX.IN-ADDR.ARPA TTL=(1440) PTR=[corp.forptr.21cn.com]
Tue 2012-09-04 09:58:54: *  Gathering A records...
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: *  D=corp.forptr.21cn.com TTL=(45) A=
Tue 2012-09-04 09:58:54: ---- End PTR results
Tue 2012-09-04 09:58:54: Performing IP lookup (corp.21cn.com)
Tue 2012-09-04 09:58:54: *  D=corp.21cn.com TTL=(5) A=[58.211.81.104]
Tue 2012-09-04 09:58:54: ---- End IP lookup results
Tue 2012-09-04 09:58:54: Performing IP lookup (BBB.cn)
Tue 2012-09-04 09:59:54: *  DNS: 60 second wait for DNS response exceeded
Tue 2012-09-04 09:59:54: *  P=010 S=000 D=BBB.cn TTL=(60) MX=[mta-ent.21cn.com] {XXX.14.XXX.73}
Tue 2012-09-04 09:59:54: ---- End IP lookup results
Tue 2012-09-04 09:59:54: --> 250 <zhouying@BBB.cn>, Sender ok
Tue 2012-09-04 09:59:54: 连接关闭
Tue 2012-09-04 09:59:54: SMTP session terminated (Bytes in/out: 63/248)
Tue 2012-09-04 09:59:54: ----------

还是这样的问题。。从字面上看，好像是DNS服务器查询超时导致连接关闭。更换DNS服务器不知道能不能解决此问题。我已经将查询时间调到60秒，结果还是出错。
请帮忙看看是什么问题。

好多个公司发过来的邮件都拒收。都是一些像163、126、QQ、21cn之类的企业邮箱。

我公司邮件服务器没有开SSL和TLS