DOCUMENT:Q193323  09-MAY-1999  [exchange]
TITLE   :XCON: Eicon X.25 Limited to Control Block Value of 32
PRODUCT :Microsoft Exchange
PROD/VER:WINDOWS:4.0,5.0,5.5
OPER/SYS:
KEYWORDS:

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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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IMPORTANT: This article contains information about editing the registry.
Before you edit the registry, make sure you understand how to restore it if
a problem occurs. For information about how to do this, view the "Restoring
the Registry" Help topic in Regedit.exe or the "Restoring a Registry Key"
Help topic in Regedt32.exe.

SYMPTOMS
========

Customers may report that their X.25 connection is no longer working. Symptoms
of this behavior can be tracked down with Event Viewer by setting the logging
for the diagnostic option "X.400 service" to Medium. This should produce the
following event:

  Event Id: 252
  Source: MSExchangeMTA
  Description: An internal MTA error has occurred.  No supporting stack
               configured for OSI entity : %1\n

Logging will also register another event:

  Event Id: 9106
  Source: MSExchangeMTA
  Description: An internal MTA error occurred. The X.25 interface
               failed to initialize. Check to make sure the X.25 card
               is started.

When you use Eicon's diagnostics ECMODULE, STATUS X25 shows no "x25listen"
application. An Eicon Trace shows only incoming calls, which will be refused
right away with Clear code 40 (Call set up, clearing, or registration problem).

CAUSE
=====

Microsoft Exchange Server configured with the Eicon X.25 stack may be set to an
incorrect number of control blocks or virtual circuits.

WORKAROUND
==========

WARNING: Using Registry Editor incorrectly can cause serious problems that may
require you to reinstall your operating system. Microsoft cannot guarantee that
problems resulting from the incorrect use of Registry Editor can be solved. Use
Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And
Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete
Information in the Registry" and "Edit Registry Data" Help topics in
Regedt32.exe. Note that you should back up the registry before you edit it. If
you are running Windows NT, you should also update your Emergency Repair Disk
(ERD).

1. Start Registry Editor (Regedt32.exe).

2. Locate the "Eicon X.25 Connections" value under the following key in the
   registry:

      HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeMTA
      \Parameters
     

   NOTE: The above registry key is one path; it has been wrapped for readability.

3. Verify that this value (DWORD) has NOT been configured for a value greater
   than 32 decimal. If it has, change the setting to less than 32 decimal. See
   the More Information section below.

4. Quit Registry Editor.

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

Microsoft Exchange Server configured with the Eicon X.25 stack can only support
up to 32 control blocks or virtual circuits. If any more than 32 control blocks
are configured, error 9106 will be logged at initialization, and no X.25
functions will be available.

Additional query words: X.25, Eicon, X25

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Keywords          :  
Technology        : kbExchangeSearch kbExchange500 kbExchange550 kbExchange400 kbZNotKeyword2
Version           : WINDOWS:4.0,5.0,5.5
Issue type        : kbprb

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