DOCUMENT:Q166308  29-APR-1999  [exchange]
TITLE   :XCON: Exchange MTA Logs NT Event ID 51
PRODUCT :Microsoft Exchange
PROD/VER:WinNT; Exchange 4.0, 5.0. 5.5
OPER/SYS:
KEYWORDS:kbtshoot kbusage

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The information in this article applies to:

 - Microsoft Exchange Server, versions 4.0, 5.0, 5.5 
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SYMPTOMS
========

A Windows NT event ID 51 appears in the event log on a computer running
Microsoft Exchange Server with configured X.400 connectors.

   3/7/97 8:23:42 PM
   MSExchangeMTA
   Warning Security  51
   N/A
   <Exchange_server_name> An unknown MTA has attempted to bind. The MTA
   name in bind is <other_mta_host>. The MTA presentation address is
   /n:0x636166656F6C65, Association index: 2354. [MTA XFER-IN 23 42] (14)

CAUSE
=====

A remote message transfer agent (MTA) has attempted to establish a messaging
session with the computer running Exchange Server and there has been a mismatch
in the specified security information. The security information for the computer
running Exchange Server is specified on the remote MTA name or Password fields,
the T, S and P selector in the Outgoing and Incoming OSI address information,
and the local MTA name or password fields on the Override tab of the Exchange
connector. Improper entry of any one or a combination of these results in a
security violation.

The Remote and the Local password fields are case-sensitive and must be an exact
match with the information submitted by the adjacent MTA when it attempts to
connect (bind). The T, S and P Selector may be entered in either hexadecimal or
text; verify that only the required fields are specified and that the required
fields are specified in the correct format. If multiple X.400 connectors use a
given transport stack to connect to foreign X.400 MTAs, verify that each of the
connectors has a unique value specified for the T Selector (TSAP). The T
Selector specifies the entry point to the transport layer of the protocol and as
such should be unique.

MORE INFORMATION
================

Remote MTA name and password fields on the General tab and the Open Sytems
Interconnect (OSI) information for Outgoing and Incoming OSI address information
are on the Stack tab of the X.400 connector configuration dialog box. P Selector
(PSAP) is not supported in 1984 mode. S Selector (SSAP) is not supported in 1988
X.410 mode. T Selector (TSAP) is the most uniformly used throughout X.400 MTAs.

Additional query words: X400
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Keywords          : kbtshoot kbusage 
Technology        : kbExchangeSearch kbExchange500 kbExchange550 kbExchange400 kbZNotKeyword2
Version           : WinNT; Exchange 4.0, 5.0. 5.5

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