Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Tue, 26 Aug 2008 17:07:42 +0300

The original message was received at Tue, 26 Aug 2008 17:07:36 +0300
from [66.206.34.181]

   ----- The following addresses had permanent fatal errors -----
<[email-masked]>
    (reason: 550 5.1.1 User unknown)

   ----- Transcript of session follows -----
... while talking to [192.168.1.240]:
>>> DATA
<<< 550 5.1.1 User unknown
550 5.1.1 <[email-masked]>... User unknown
<<< 503 5.5.2 Need Rcpt command.