From: ksdom.kr PostMaster [mailto:****@****]
 Sent: Friday, August 19, 2011 9:14 AM
 To: ****@****
 Subject: Error sending message [***-****-*******-****-****64.8a4d.eml] from
 [ksdom.kr]
 
 [<00] XMail bounce: Rcpt=[****@****];Error=[554-msg-ironport1.usc.edu
 554 Your access to this mail system has been rejected due to the sending
 MTA's poor reputation. If you believe that this failure is in error, please
 contact the intended recipient via alternate means.]
 
 
 [<01] Error sending message [***-****-*******-****-****64.8a4d.eml] from
 [ksdom.kr].
 
 ID: <S60811F
 Mail From: <****@****
 Rcpt To: <****@****
 Server: <mx.usc.edu [128.125.253.79]
 
 
 [<02] The reason of the delivery failure was:
 
 554-msg-ironport1.usc.edu
 554 Your ! access to this mail system has been rejected due to the sending
 MTA's poor reputation. If you believe that this failure is in error, please
 contact the intended recipient via alternate means.
 
 
 [<04] Here is listed the message log file:
 
 [PeekTime] ***-****-**** : Fri, 19 Aug 2011 09:13:53 +0900
 <<
 ErrCode = -41
 ErrString = Bad server response
 ErrInfo = 554-msg-ironport1.usc.edu
 554 Your access to this mail system has been rejected due to the sending
 MTA's poor reputation. If you believe that this failure is in error, please
 contact the intended recipient via alternate means.
 SMAIL SMTP-Send MX = "mx.usc.edu." SMTP = "ksdom.kr" From =
 "****@****" To = "****@****" Failed !
 SMTP-Error = "554-msg-ironport1.usc.edu
 554 Your access to this mail system has been rejected due to the sending
 MTA's poor reputation.! If you believe that this failure is in error, please
 contact the intended recipient via alternate means."
 SMTP-Server = "mx.usc.edu."
 
 
 
 [<05] Here is listed the initial part of the message:
 
 X-AuthUser: ****@****
 Received: from userPC01 ([203.251.128.102]:39671)
 by ksdom.kr with [XMail 1.22 PassKorea100519 - Second ESMTP Server]
 id <S60811F for <****@**** from <****@****;
 Fri, 19 Aug 2011 09:13:52 +0900
 From: "Areum Han" <****@****
 To: "'Beth Saul'" <****@****
 References: <000301cc525c$a3dfbe00$eb9f3a00$@kr
 <00c301cc52ca$b8a7d520$29f77f60$@usc.edu
 <000b01cc530c$5a97ea00$0fc7be00$@kr
 <00a101cc538e$cd732a80$68597f80$@usc.edu
 <001f01cc5d62$697efd50$3c7cf7f0$@kr
 <013001cc5de2$5bb32180$13196480$@usc.edu
 In-Reply-To:
 Subject: RE: Trojan Parents Network fro! m Korea
 Date: Fri, 19 Aug 2011 09:14:33 +0900
 Message-ID: <000e01cc5e04$f99ae5a0$ecd0b0e0$@kr
 MIME-Version: 1.0
 Content-Type: multipart/alternative;
 boundary="----=_NextPart_000_000F_01CC5E50.69828DA0"
 X-Mailer: Microsoft Office Outlook 12.0
 Content-language: ko
 Thread-index:
 AQD+kK8gAxjJ9NFJO4wToly50HGOBgFauPjFAwzeWwoB5xnCCAG6pPIAln5YkNCAAEFw0IAAA8uw

위와 같이 메세지가 나오며  현재 국내에서 외국으로 발송중인대 자꾸 반송 메일이 오고있습니다.

이유를 알려주시기 바랍니다.