IOT has received numerous reports from individuals concerned about “undeliverable” message notifications from addresses to which they did not send a message. The cause is most likely a SPAMMER. Here is a common scenario:
From: Mail Delivery System [mailto:MAILER-DAEMON@xxyyzz.com]
Sent: Monday, April 07, 2008 9:39 AM
To: Doe, John
Subject: Undelivered Mail Returned to Sender
This is the mail system at host mx2.xxyyzz.com.
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 mail system