Emails sent from Internet or application created emails are not delivered to users
Original KB number: 2519912
Symptoms
Some email messages received from external organizations or application-generated email messages are not delivered to users.
You receive the following NDR:
#554 5.6.0 STOREDRV.Deliver; Corrupt message content ##
Cause
If you check the message headers for the format of the message:
Content-Type: application/mac-binhex40
Content-Transfer-Encoding: base64
You notice the qualifying line: Content-Transfer-Encoding: base64 for mac-binhex type of document.
This indicates that the actual data is base64 encoded.
Since Exchange Server only accepts the RFC standard mac-binhex encoding, these messages are rejected.
Resolution
The sender should be sending the attachment in correctly formatted mac-binhex40 format.
The correctly formatted mac-binhex40 message header should have the following Content lines:
Content-Type: application/mac-binhex40
Content-Disposition: attachment; filename="example.doc"
Indicating that the document is encoded using the RFC standard mac-binhex40 format.
More information
As per the Appendix A. The BinHex format part in RFC 1741 - MIME Content Type for BinHex Encoded Files:
Here is a description of the Hqx7 (7 bit format as implemented in BinHex 4.0) formats for Macintosh Application and File transfers.
The main features of the format are:
1. Error checking even using ASCII download
2. Compression of repetitive characters
3. 7 bit encoding for ASCII download
The format is processed at three different levels:
1. 8 bit encoding of the file:
Byte: Length of FileName (1->63)
Bytes: FileName ("Length" bytes)
Byte: Version
Long: Type
Long: Creator
Word: Flags (And $F800)
Long: Length of Data Fork
Long: Length of Resource Fork
Word: CRC
Bytes: Data Fork ("Data Length" bytes)
Word: CRC
Bytes: Resource Fork ("Rsrc Length" bytes)
Word: CRC
2. Compression of repetitive characters.
($90 is the marker, encoding is made for 3->255 characters)
00 11 22 33 44 55 66 77 -> 00 11 22 33 44 55 66 77
11 22 22 22 22 22 22 33 -> 11 22 90 06 33
11 22 90 33 44 -> 11 22 90 00 33 44
The whole file is considered as a stream of bits. This stream will
be divided in blocks of 6 bits and then converted to one of 64
characters contained in a table. The characters in this table have
been chosen for maximum noise protection. The format will start
with a ":" (first character on a line) and end with a ":".
There will be a maximum of 64 characters on a line. It must be
preceded, by this comment, starting in column 1 (it does not start
in column 1 in this document):
For more information, you can also reference 2.2.4.2.3 Application/Mac-binhex40.
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