DOCUMENT:Q153815  30-AUG-2001  [exchange]
TITLE   :XCLN: Exchange Client Cannot Send Mail Across Router
PRODUCT :Microsoft Exchange
PROD/VER::4.0
OPER/SYS:
KEYWORDS:kberrmsg kbusage

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The information in this article applies to:

 - Microsoft Exchange Server, version 4.0 
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SYMPTOMS
========

You can send and receive mail in a Microsoft Exchange client for Chinese Windows
3.x only when you are on the same network segment as the Microsoft Exchange
Server. If the Microsoft Exchange Server is located on the other side of an
Ethernet router, you can only read mail. When you attempt to send mail, you
receive the following error message:

   The item could not be sent. Network problems are preventing connection to the
   Microsoft Exchange Server computer

CAUSE
=====

This can happen if the message is being sent over IPX and the router MTU for IPX
is set to only pass packets that are smaller than the Microsoft Exchange client
is using.

WORKAROUND
==========

Configure the Microsoft Exchange Server and the Novell ODI driver to send out
IPX packages equal or smaller than the MTU value. The following example shows
how to set the value to 576 bytes.

To do this on the Microsoft Exchange Server, start Regedt32.exe and change to:

   \HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\ServicesNwlnkIpx
                      \Netconfig\driver01

Now increase the following registry value, note that this is hexidecimal:

   MaxPktSize: REG_DWORD: 0X240

At the client, add following lines to your Net.cfg file:

   Protocol ipx
   ipx packet size limit 576

Additional query words:

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Keywords          : kberrmsg kbusage 
Technology        : kbExchangeSearch kbExchange400 kbZNotKeyword2
Version           : :4.0

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