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

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.