XADM: Missing MIME Boundary Causes Bad MIME Prolog

ID: Q217155

The information in this article applies to:

Microsoft Exchange Server, version 5.5

SYMPTOMS

When Microsoft Internet Mail Service receives a MIME-encoded message that has a large MIME prolog and the message is relayed, an endless loop in content conversion may result in a temporary file with an .stf extension that grows until all the disk space is consumed or the Internet Mail Service is shut down. The .stf file can also grow as a result of a POP3 or IMAP4 client downloading mail from the server.

CAUSE

This problem is typically because of a missing boundary before a body part causing the body part to be interpreted as part of the prolog. If the prolog is big enough to be within approximately 76 bytes of the current available buffer space, the prolog is emitted but leaving no room for the boundary to fit in. This results in an endless loop of emitting the same prolog over and over again while the temporary file grows in size.

A typical example would be:

Content-Type: multipart/alternative; boundary="---- _=_NextPart_001_01BE4633.82DAE140"
Content-Type: text/plain

A missing boundary here makes the all of this portion to be prolog:


===========================================
AAAAAAA AA AAAAAAA AAAAAAA AA AAA AAAA AAAAA AAAA  AAAA AAAAAAA.

AAA AA AA AAAA AAAAAAAA AAAAAA AAAA AAAAAAAA AA AAA AAA AAAAAAAA?

BBBBBBB BBBBBBB, BBBBBB, BBBBBBBB B, BBBB, BBBBBB B BBBBBB
CCCCCCCCCCCCCCCCCCCCCCC

CCC CCCC CCCC CCCCCCC DD DDD DD DD DDDDDDD, DD DD D DDDDDDDDDD
DDDDDDDDD. DDDD DD DDD DD DD DDDDD DDD DDD DDDDDDDDDD DDDDDDDD DD DDDD
DDDD DDDDDDDDDD DD DDDDDD DDD DDD DDDDDDD DDDDDDD, DDDDDDDDDDDD
DDDDDDD DDDD DDD DDDD DDDD DDD DDD DDDDDDDDDDDDDDDDDD DDDDDDDD.
DDDDDD DDDD DDDDDDD, DDDDDDDD DDDD DDDDDDD DDD DDDDDD DD DDDDDDD DDDDD'D
EEE EEEEEEEEEE EEEE EEEEEEE EEEEEE EEEEE EEEEEE EEE EEEEEEEE
EEEEEE, EEEE EEEEEEEE EEEEEEEEEEEEEEEEEE EEEEEEEE.

EEEEEEEEE EEEEEEE EEEEEEE: EEEEEEE, EEEEEE EEEEEEE, EEEEEEEE,
EEEEEE EEEEEEE EEEEEEEEE EE EEE

EEEE EEEEEEE
FFFFFFFFFFFFFFF
============================================
  <<FFFFFFF_FFFFF_FFFF_FFFFFFFFFFFFFF>>
Prolog Ends here
------_=_NextPart_001_01BE4633.82DAE140

RESOLUTION

To resolve this problem, obtain the latest service pack for Exchange Server version 5.5. For additional information, please see the following article in the Microsoft Knowledge Base:

Q191014 XGEN: How to Obtain the Latest Exchange Server 5.5 Service Pack

The English version of this fix should have the following file attributes or later:

Component: Information Store

File name	Version
Gapi32.dll	5.5.2558.0
Mdbmsg.dll	5.5.2558.0
Store.exe	5.5.2558.0

STATUS

Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 5.5. This problem was first corrected in Exchange Server 5.5 Service Pack 3.

Additional query words: mdbdata large STF .STF files grow

Keywords : exc55 EXC55SP3Fix
Version : winnt:5.5
Platform : winnt
Issue type : kbbug