XCON: Incoming Messages from HP OpenMail Include Winmail.dat

Attachments on incoming messages from a Hewlett-Packard (HP) OpenMail X.400 connector may include a Winmail.dat attachment if the Microsoft Exchange Server Message Transfer Agent (MTA) is build 995.17 or higher. HP OpenMail can use Microsoft Mail clients with an HP MAPI driver.

The remote system may be sending the Winmail.dat as an FTBP of type mapiAttachment. This is the same value being used for attached files. Normally, the Winmail.dat file is tagged as type TNEF. When the MTA sees the mapiAttachment tag, it assumes it is just another bodypart, and handles it accordingly. If the bodypart was tagged as type TNEF, the MTA would parse it out and use the details inside.

MapiAttachment uses the OID 0x2a864886f714030a02

TNEF uses the OID 0x2a864886f714030a01

The OID can be seen in the ASN.1 parsed data in the attribute P2_RegisteredIdentifier. Microsoft provides an ASN.1 parser in the BackOffice Resource Kit called Aspirin.

Configure the HP OpenMail MAPI driver to not generate a Winmail.dat file on outgoing messages. This is done in the Msmail.ini file, in the following section: If EncodeAttachInfo is "0", the Winmail.dat file will not be generated. If it is a "1", the Winmail.dat file will be generated.

If the workaround is impractical to implement, see the status section for a possible resolution.

Microsoft has confirmed this to be a problem in Microsoft Exchange Server, version 4.0. This problem has been corrected in the latest U.S. Service Pack for Microsoft Exchange Server version 4.0. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):
Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 5.0. This problem has been corrected in the latest U.S. Service Pack for Microsoft Exchange Server version 5.0. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces):