메일 내용 분석 좀 부탁 드립니다.

sendmail 의 /var/mail/root 메일에 다음과 같은 유형의 비슷한 메세지들이 100여건을 아웃룩으로 받았는데 무슨 경우 인가요?

Return-Path: <MAILER-DAEMON@localhost.localdomain>
Received: from localhost (localhost)
 by localhost.localdomain (8.12.8/8.12.8) id i6JMKI32001789;
 Tue, 20 Jul 2004 07:20:29 +0900
Date: Tue, 20 Jul 2004 07:20:29 +0900
From: Mail Delivery Subsystem <MAILER-DAEMON@localhost.localdomain>
Message-Id: <200407192220.i6JMKI32001789@localhost.localdomain>
To: postmaster@localhost.localdomain
MIME-Version: 1.0
Content-Type: multipart/report; report-type=delivery-status;
 boundary="i6JMKI32001789.1090275629/localhost.localdomain"
Subject: Postmaster notify: see transcript for details
Auto-Submitted: auto-generated (postmaster-notification)
Status:  

Return-Path: <MAILER-DAEMON@localhost.localdomain>
Received: from localhost (localhost)
 by localhost.localdomain (8.12.8/8.12.8) id i6K4cNKs001844;
 Tue, 20 Jul 2004 13:38:25 +0900
Date: Tue, 20 Jul 2004 13:38:25 +0900
From: Mail Delivery Subsystem <MAILER-DAEMON@localhost.localdomain>
Message-Id: <200407200438.i6K4cNKs001844@localhost.localdomain>
To: postmaster@localhost.localdomain
MIME-Version: 1.0
Content-Type: multipart/report; report-type=delivery-status;
 boundary="i6K4cNKs001844.1090298305/localhost.localdomain"
Subject: Postmaster notify: see transcript for details
Auto-Submitted: auto-generated (postmaster-notification)
Status: