SUMMARY - Bizarre sendmail gets wrong MX value!!

From: Peter Stokes <>
Date: Thu Aug 28 2003 - 08:09:03 EDT
Hi All

Thanks for the replies.

All stated that it was a DNS issue and to look at where the MX record
was coming from.

To confirm questions asked

The /etc/resolv.conf was identical on both machines and there was only
one nameserver listed and only one MX record for the domain, so the DNS
side of things was fine. I only had nslookup which worked fine.

I then tried a different domain mail address and that failed completely.
So on to truss and using the -d8.8 option for sendmail to see what files
were being called.

Working through this I checked each file referenced and evenmtually came
up with /etc/nsswitch.conf which DID NOT have dns as one of the host
lookup options. How it managed to get the original domain address in the
first place I have no idea unless it had cached it from nslookup and was
getting the address that way.

So adding dns to nsswitch resolved it immediately (no need for reboot)

Thanks to all that replied (not many Out of Office, so must be end of
holiday season)



Original Message

Hi All

Hope you can help me with this one as it makes no sense to me

I two systems which I loaded and should have the same version of 2.6
installed (they were loaded 1+ years ago and have differing packages
loaded). I have setup both to simply send mail out without using a
mailhub ( in /etc/mail).

One system works no problem, the other appears after comparing sendmail
debug options to NOT pickup the MX record for the domain it is sending
to correctly and I think picks up the A record instead, because it tries
to send the mail to the webserver of the domain instead of the
mailserver for the domain and hence gets a reject from the mailer on the

Now both machines are running the same (V8.8.8+Sun version
sendmail) and both are on the same subnet.

When I run the -d8.8 with sendmail I get no MX info from the failing
one, only on the working one.

Any clues where to look as I guess it is some sort of library issue?


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Received on Thu Aug 28 08:08:53 2003

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