XFOR: IMC Doesn't Appear to Use All Mail Exchangers (150114)


The information in this article applies to:

  • Microsoft Exchange Server 4.0
This article was previously published under Q150114

SUMMARY

When you compare the results between Nslookup.exe and Restest.exe, it may appear that the Microsoft Exchange Internet Mail Connector (IMC) is not resolving all mail exchangers for a given domain.

MORE INFORMATION

For example, you may notice a discrepancy between the number of mail exchangers listed by Restest.exe and Nslookup.exe on the following query.

Below is a sample run of Restest.exe: 
C:\my documents>e:restest -debug aol.com

   ***   Matches Microsoft Exchange Server build 4.0.0736   ***

host[0] = '198.81.11.33'
host[1] = '198.81.11.14'
host[2] = '198.81.11.37'
host[3] = '198.81.11.15'
host[4] = '198.81.11.52'

Notice that Restest.exe displays 6 mail exchangers for AOL.COM. Nslookup.exe appears to show more mail exchangers.

Below is a sample run of Nslookup.exe: 
> server hp81.prod.aol.net
Default Server:  hp81.prod.aol.net
Address:  192.203.190.18

> set type=MX
> aol.com.
Server:  hp81.prod.aol.net
Address:  192.203.190.18

aol.com preference = 15, mail exchanger = e.mx.aol.com
aol.com preference = 15, mail exchanger = f.mx.aol.com
aol.com preference = 15, mail exchanger = a.mx.aol.com
aol.com preference = 15, mail exchanger = b.mx.aol.com
aol.com preference = 15, mail exchanger = c.mx.aol.com
aol.com preference = 15, mail exchanger = d.mx.aol.com
aol.com nameserver = ops01.ops.aol.com
aol.com nameserver = dns-aol.ans.net
aol.com nameserver = hp81.prod.aol.net
e.mx.aol.com    internet address = 198.81.11.18
e.mx.aol.com    internet address = 198.81.11.20
e.mx.aol.com    internet address = 198.81.11.12
e.mx.aol.com    internet address = 198.81.11.15
f.mx.aol.com    internet address = 198.81.11.51
f.mx.aol.com    internet address = 198.81.11.52
f.mx.aol.com    internet address = 198.81.11.53
f.mx.aol.com    internet address = 198.81.11.54
f.mx.aol.com    internet address = 198.81.11.50
a.mx.aol.com    internet address = 198.81.11.28
a.mx.aol.com    internet address = 198.81.11.29
a.mx.aol.com    internet address = 198.81.11.30
a.mx.aol.com    internet address = 198.81.11.11
b.mx.aol.com    internet address = 198.81.11.32
b.mx.aol.com    internet address = 198.81.11.33
b.mx.aol.com    internet address = 198.81.11.13
b.mx.aol.com    internet address = 198.81.11.31

Although Nslookup.exe shows many more IP addresses listed for aol.com, there are still only 6 mail exchangers (a.mx.aol.com .. f.mx.aol.com). AOL has multiple, redundant hosts listed for each mail exchanger.

Microsoft Exchange, and Restest.exe, are working correctly.
Modification Type:MinorLast Reviewed:4/28/2005
Keywords:kbusage KB150114
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