DOCUMENT:Q191594  14-APR-1999  [exchange]
TITLE   :XCON: Site Connector Not Usable Through a Firewall
PRODUCT :Microsoft Exchange
PROD/VER:WinNT:5.5
OPER/SYS:
KEYWORDS:exc55sp2fix

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The information in this article applies to:

 - Microsoft Exchange Server, version 5.5 
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SYMPTOMS
========

According to the Microsoft Knowledge Base article Q161931, "XCON: Configuring
MTA TCP/IP Port # for X.400 and RPC Listens," two Exchange Server computers in
different sites can be configured to communicate through a firewall by setting
the desired port numbers for RPC Listens. However, if the firewall filters
incoming and outgoing ports, no mail is flowing and the event log shows the
following 9322 error:

   An interface error has occurred. An MtaBindBack over RPC has failed.
   Locality Table (LTAB) index: %1, NT/MTA error code: %2. Comms error %3,
   Bind error %4, Remote Server Name %5, Protocol String %6 [%7 %8 %9 %10]
   (14)

CAUSE
=====

The calling Exchange Server MTA issues a RPC bind command that contains a TCP
port number to be used in the reply, the bindback RPC command. When replying,
the called MTA does not use this port number, and as the firewall is configured
to let go through only this port number, the reply is never received by the
calling MTA. The communication is not established and as a result no mail can be
sent or received.


RESOLUTION
==========

To resolve this problem, obtain the latest service pack for Exchange Server
version 5.5. For more information, please see the following article in the
Microsoft Knowledge Base:

   Q191014 : XGEN: How to Obtain the Latest Exchange Server 5.5 Service Pack




STATUS
======

Microsoft has confirmed this to be a problem in Microsoft Exchange Server
version 5.5.

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Keywords          : exc55sp2fix 
Technology        : kbExchangeSearch kbExchange550 kbZNotKeyword2
Version           : WinNT:5.5
Issue type        : kbbug
Solution Type     : kbfix

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