XCLN: Exchange Client Cannot Send Mail Across Router

 Last reviewed: March 28, 1997
Article ID: Q153815
The information in this article applies to:
  • Microsoft Exchange Server, version 4.0

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:
Keywords : kbusage XCLN
Version : 4.0 5.0
Platform : WINDOWS

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Last reviewed: March 28, 1997
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