Return-Path: <MAILER-DAEMON@example.com>
Received: from mx8.example.com ([192.0.2.59])
    by mx4.example.com (Post.Office MTA v3.1.2 release (FF000+0900) 
    ID# 0+09000000000000000) with SMTP id 0000000 
    for <shironeko@example.co.jp>;
    Thu, 29 Apr 1999 23:34:45 +0900
Received: by mx8.example.com; (5.65/1.37) id 0000000; 
    Thu, 29 Apr 1999 23:34:45 +0900
Date: Thu, 29 Apr 1999 23:34:45 +0900
From: Mail Delivery Subsystem <MAILER-DAEMON@example.com>
Subject: Returned mail: User unknown
Message-Id: <00000000000.0000000@x8.example.com>
To: shironeko@example.co.jp
   ----- Transcript of session follows -----
While talking to mailin1.example.org:
>>> MAIL From:<shironeko@example.co.jp>
<<< 501 <shironeko@example.co.jp>... no access from mail server [192.0.2.55] which is an open relay.
554 <kijitora@example.org>... Remote protocol error
550 example.org (smtp)... 550 Host unknown
554 <mikeneko@example.org>... 550 Host unknown (Authoritative answer from name server)
While talking to smtp.example.edu:
>>> RCPT To:<hachiware@example.edu>
<<< 550 <hachiware@example.edu>... User unknown
550 <hachiware@example.edu>... User unknown
   ----- Unsent message follows -----
Received: by mx8.example.com; (5.65/1.37) id 0000000;
    Thu, 29 Apr 1999 23:34:45 +0900
From: shironeko@example.co.jp
To: kijitora@example.org
Subject: Nyaaaaaan
Nyaaaaan