XCON: MTA: Line Wrap When Using ISO 6937 Bodypart (154719)

SYMPTOMS

When you configure the X.400 Connector to use the ISO 6937 bodypart to transfer messages to a remote X.400 system, a line wrap occurs after 80 characters. This is true even if the X.400 Connector is not configured for message text word-wrap. This may cause problems on the receiving side (for example, when sending data such as Postscript over a connector using ISO 6937).

CAUSE

The "X/Open CAE API to Electronic Mail" specification recommends a line- length limit of 80 characters in the ISO 6937 bodypart. This specification was replaced by ISO 14361, which also supports the following limitation:

Each line may contain 0-80 graphic characters for guaranteed rendition.

However, in the ISO 6937 definition, there is no such limitation, and there may be cases when enforcing this limitation may not be desirable. The following is a quote from the ISO 6937 standard:

   iso6937BodyPart DEFINITIONS EXPLICIT TAGS ::=
   BEGIN
   BodyPart ::= CHOICE {
            [0]  IMPLICIT ISO646Text,
            [1]  IMPLICIT TLX,
            [2]  IMPLICIT Voice,
            [3]  IMPLICIT G3Fax,
            [4]  IMPLICIT TIF0,
            [5]  IMPLICIT TTX,
            [6]  IMPLICIT Videotex,
            [7]  NationallyDefined,
            [8]  IMPLICIT Encrypted,
            [9]  IMPLICIT ForwardedIPMessage,
            [10] IMPLICIT SFD,
            [11] IMPLICIT TIF1,
            [12] IMPLICIT ODA,
            [13] IMPLICIT ISO6937Text}

   ISO6937Text ::= SEQUENCE {
      SET { repertoire [0] IMPLICIT INTEGER OPTIONAL
      SEQUENCE OF ISO6937Line }
   ISO6937Line ::= [0] IMPLICIT OCTET STRING
   END

STATUS

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

S E R V P A C K

MORE INFORMATION

This fix changes the behavior of an X.400 Connector using ISO 6937. If message text word-wrap is set to Never, the length of a line in the message body is no longer limited.

When implementing this fix, an administrator should be aware that it may affect the interoperability with remote X.400 message transfer agents (MTAs). This will be true if a remote X.400 MTA expects the length of a line to be limited to 80 characters. If there are any X.400 MTAs connected that do expect the limitation, you need to set the message text word-wrap.