Getting lots of Undeliverable: Returned mail: see transcript for details

[Jon Radel]

Scott Silva wrote:
> Billy A. Pumphrey spake the following on 4/15/2006 7:53 PM:
> 
>>Since I upgraded to near the latest MailScanner, I am getting a lot of
>>these.
>>
>>Your message did not reach some or all of the intended recipients.
>>
>>      Subject:	Returned mail: see transcript for details
>>      Sent:	4/15/2006 9:32 PM
>>
>>The following recipient(s) could not be reached:
>>
>>      jelki at selena.net.ua on 4/15/2006 9:32 PM
>>            The message could not be delivered because the recipient's
>>destination email system is unknown or invalid. Please check the address
>>and try again, or contact your system administrator to verify
>>connectivity to the email system of the recipient.
>>            < WoodenMS2.woodmaclaw.local #5.1.2>	
>>
>>Any idea why this is happening?  I figure that is is DNS related or
>>something.
>>
>>Thank you
> 
> I tried a smtp verify on that user at that domain;
> User does not exist....
> 
> 

It would possibly make more sense if Mr. Pumphrey read down a bit and 
looked at the rest of the mail (aren't the original e-mails attached?). 
  I see a lot of those in the postmaster, address of last resort, e-mail 
from the following:

1) Spam from non-existent address is sent to non-existent user on my 
sendmail server.

2) Bounce to non-existent from address is prepared.

3) Bounce bounces and notice of this second bounce goes to postmaster.

I suspect that as part of the upgrade either the option to quietly 
discard these was turned off in the MTA or MailScanner is no longer 
"discarding" them.  I suspect the root cause was there before.

--Jon Radel
jon at radel.com