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方法一
Question/Problem: When I try to send mail to another server I get a 'Stack connect fail "ip.ad.dr.ess"' error.
Answer/Solution: A stack connect fail occurs when the DNS query for the remote domain fails. Assuming that the DNS information for the remote domain is valid (you can use WS_Ping ProPack or www.dnsstuff.com to test this) the issue can occur for one of three reasons:
1.) The DNS server that IMail is querying is malfunctioning.
- Try using a different DNS server. IMail's Domain Name Server address field (on the SMTP tab) supports multiple DNS servers separated by a space, but during troubleshooting, use one DNS server at a time. When changing DNS information, be sure to restart the SMTP and Queue Manager services.
- If you have access to the DNS server logs, check them to see if they received the query from IMail and if they were able to respond to it.
2.) A network issue is preventing the DNS queries from succeeding. This could be the result of dropped data or data being corrupted during transmission.
- Check to make sure that no outbound traffic from the IMail server is being filtered.
- A packet sniffer/filter installed on the IMail server would be able to track the lost/corrupt packets.
3.) (Does not apply after version 8.12.) Another DNS device on the same server is conflicting with IMail's DNS resolver.
- IMail's DNS resolver listens on port 53. Another DNS device (such as a DNS server) running on the same computer as IMail will cause issues.
大意是说,如果有Stack connect fail 的报错信息,先检查DNS,要一个一个地试,每试一次,SMTP 和 Queue Manager services重启一次;其次看是不是杀毒软件将邮件过滤了;再看imail的DNS与服务器本身的DNS是不是冲突了.
方法二:
如果有SMTP connect fail 的报错信息.
A ) 用nslookup命令
1.测试对方的域名是否可以解析,如果不能解析则可能这一时刻对方的DNS服务器故障。导致通讯邮件发送失败。
2.获得对方的MX(邮件)纪录
运行:CMD 键入:NSLOOKUP 命令。
进入操作界面,操作提示符如下:
>
表示开始接受命令状态。
第一个:SERVER
进入NSLOOKUP后,系统会将默认的SERVER设置为你当前获得的DNS SERVER。显示如下
>Default Server: dns.me.com
>Address: 10.10.10.2
>
有时候因为CACHE的原因,我们需要用外部更好的DNS SERVER来帮助我们完成测试。比如我LAN网内的DNS为10.10.10.2,为了更快更好的获得结果,我需要用广东省的铁通的DNS服务器来帮我完成测试,则敲入:
键入:
>SERVER 211.98.2.4
显示为:
>Default Server: ns.cn-railway.net
>Address: 211.98.2.4
>
表示当前默认的DNS解析服务器更改为211.98.2.4,随后我们敲入的请求都将从这台服务器获得反馈。我们可以测试一下键入:
> 163.com
Server: [ ns.cn-railway.net]
Address: 211.98.2.4
Non-authoritative answer:
Name: 163.com
Addresses: 202.106.168.103, 202.106.168.104, 202.106.168.109, 202.106.168.121
202.108.36.153
这里得到的是163.com域名中www这个主机的IP。一般情况下只会有一个IP纪录。为什么有这么多呢?这里牵涉到DNS循环来解决服务器负担问题。我们不做详细介绍。
第二个:SET TYPE=MX (SET Q=MX)
通常进入NSLOOKUP,默认操作类型为A纪录.但是我们要解决的是邮件问题,当然需要查看的是邮件MX纪录。也就是发送给 abc@163.com 的邮件会送到哪台邮件服务器上去。 这条命令就告诉服务器,我需要获得该域名的邮件纪录。set type=mx set q=mx 效果是一样的。当然如果你要察看A纪录,也可以用set q=A 切换。
键入命令:
>set q=mx
再敲:
>163.com
得到不同结果如下:
Server: [ ns.cn-railway.net]
Address: 211.98.2.4
Non-authoritative answer:
163.com MX preference = 50, mail exchanger = mx.mail.163.com
mx.mail.163.com internet address = 202.108.44.208
mx.mail.163.com internet address = 202.108.44.209
mx.mail.163.com internet address = 202.108.44.210
mx.mail.163.com internet address = 202.108.44.211
mx.mail.163.com internet address = 202.108.44.215
mx.mail.163.com internet address = 202.108.44.223
mx.mail.163.com internet address = 202.108.44.224
mx.mail.163.com internet address = 202.108.44.228
mx.mail.163.com internet address = 202.108.44.133
mx.mail.163.com internet address = 202.108.44.154
mx.mail.163.com internet address = 202.108.44.155
mx.mail.163.com internet address = 202.108.44.180
mx.mail.163.com internet address = 202.108.44.203
mx.mail.163.com internet address = 202.108.44.207
由上可知,邮件纪录会发送给mx.mail.163.com这台服务器。同样下面列出很多条纪录对应到不同IP,都是处于缓解服务器负担,以及备用,分流作用。
特别注意:
1.请多更换几台DNS服务器进行测试,因为不同的DNS会因CACHE不同而得到不同的结果。这样比较准确的判断是否为对方的DNS故障,或者是自己的DNS服务故障。
2.如果使用NSLOOKUP在同一DNS服务器上测试多次以及在不同的服务器上测试多次,如果无法得到A纪录或者无法得到MX纪录。则说明对方的DNS出现问题。所以导致无法通讯,发送邮件。某些时候因为网络原因会得到
DNS request timed out.
timeout was 2 seconds.
*** Request to [211.98.4.1] timed-out
类似的结果。请试多几次。
如果我们能正确获得上述信息就说明不存在该类问题。
B ) 用telnet模拟邮件会话过程
比如登录新浪
telnet freemx1.sinamail.sina.com.cn 25
helo xxx.com (您的域名)
mail from:xxx@xxx.com (您的域名存在的真实邮箱)
rcpt to:xxx@sina.com(可以使用您自己的sina邮箱)
rcpt to:email_test@sina.com(我们的测试邮箱)
data
from:xxx@xxx.com (您的域名存在的真实邮箱)
to:xxx@sina.com
to:email_test@sina.com
Subject:
随便写点儿什么,,让我们能找到您
[ 本帖最后由 data-express 于 2007-1-23 16:01 编辑 ] |
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