RE: NDR for a perticuler domain

  • From: "White, Piers" <pwhite@xxxxxxxxxxxxxxxxxx>
  • To: "[ExchangeList]" <exchangelist@xxxxxxxxxxxxx>
  • Date: Tue, 24 Sep 2002 08:37:51 -0400

This problem relates to Extended SMTP. ESMTP includes encryption on top of the 
authentication that Exchange Server uses to transfer Internet Mail. SMTP 
doesn't include this additional layer of encryption. Some systems aren't 
compliant with Internet Engineering Task Force (IETF) Request for Comments 
(RFC) 1651, which defines ESMTP commands; thus, the systems don't accept ESMTP 
commands. This limitation can result in compatibility problems when sending 
email over the Internet: The receiving email server expects an SMTP response 
from the sending email server, and the sending email server sends the response 
in ESMTP, which the receiving email server doesn't recognize. 

To solve this problem, you can disable outbound ESMTP in Exchange Server. 
However, by doing so, you lose the ability to send the ETRN command on a 
dial-up connection. ETRN is an ESMTP command that alerts one ESMTP gateway or 
mail host to process email that is waiting delivery to another SMTP mail 
handling system. If your email server is sending and receiving email over a 
leased line, this loss of ability won't be a problem. However, if you're using 
Exchange Server with DUN to retrieve email from an outside host, talk to the 
host's managers about the potential impact of disabling the ETRN command. 
Disabling ESMTP also removes the added encryption layer gained by using ESMTP 
rather than SMTP. 

To disable outbound ESMTP in Exchange Server, start regedt32, go to the 
HKEY_LOCAL_MACHINE \SYSTEM \CurrentControlSet \Services \MSExchangeIMC 
\Parameters subkey, and add the DisableOutbondESMTP subkey of data type 
REG_DWORD and a value of 1. Verify that the new value appears in the parameters 
list, close regedt32, and stop and restart the Internet Mail Service (IMS). 


-----Original Message-----
From: Zafar Pravaiz [mailto:pzafar@xxxxxxxxxxx] 
Sent: 24 September 2002 12:29
To: [ExchangeList]
Subject: [exchangelist] NDR for a perticuler domain

Hi all, 
I m using MS Exchange 5.5. this is working fine but while i m send a mail to a 
perticuler domain i m getting NDR , i can receive mail from there . This is for 
all the user of this particuler domain. Pls anybody can suggest me the cause? 

msg is like that:------- 
The following recipient(s) could not be reached:

'osama al hasan' on 9/24/2002 3:17 PM
Unable to deliver the message due to a communications failure The MTS-ID of the 
original message is: c=US;a= ;p=CUPOLA;l=SERVER01-020924111625Z-32359
MSEXCH:IMS:CUPOLA:CTSL:SERVER01 3503 (000B09AA) 503 please introduce yourself, 

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