Microsoft Exchange Hangs Sending Message Using SPX

• Microsoft Windows 95

SYMPTOMS

Microsoft Exchange or Windows Messaging may stop responding (hang) when you try to transmit a message using SPX over a dial-up connection.

This problem occurs only if the installed version of NWLINK is dated before 6/27/96 and the Wsipx.vxd file is dated before 3/5/97.

CAUSE

This problem occurs only when Microsoft Exchange or Windows Messaging is started offline and you use the Deliver Now command to deliver messages over a dial-up connection.

The problem occurs because WSIPX submits a larger frame than is supported. SPX checks the NDIS packet frame size against the connection's maximum frame size and hangs or returns a "The message cannot be delivered" error message. The NDIS packet frame size is 1497 bytes and the maximum frame size is 1160 bytes.

STATUS

Microsoft has confirmed this to be a problem in Microsoft Windows 95. An update to address this problem is now available, but should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft does not recommend implementing this update at this time. Contact your OEM or Microsoft Technical Support for additional information about the availability of this update.