Strange Postfix Delivery Failure

carlosinfl · 04-16-2008, 09:09 AM

I have a user on my LAN attempting to send email from our Postfix server to another email server and they're getting delivery failures. I don't know who is at fault here since I have no problems sending email to my <user>@cfl.rr.com account even though thats a completely separate server...

-----Original Message-----
From: Mail Delivery System [mailto:MAILER-DAEMON@example.org]
Sent: Tuesday, April 15, 2008 10:37 AM
To: terry@example.org
Subject: Undelivered Mail Returned to Sender

This is the Postfix program at host mail.example.org.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to <postmaster>

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The Postfix program

<foo@midsouth.rr.com>: Name service error for name=midsouth.rr.com
type=MX: Malformed name server reply

Anyone know what the issue could be here?

dkm999 · 04-16-2008, 10:57 AM

According to my reading of the enclosed error report, this is a DNS configuration error at midsouth.rr.com.

I just sent a query to that server, and got this back
midsouth.rr.com mail exchanger = 0 .

This is clearly wrong; if there should not be a mail exchange for this domain name, then there should not be any MX record; there is one, and it says the name of the exchanger is 0.

I would contact the admin for that zone and get them to correct their DNS configuration.