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Q194998: XCON: Client Cannot Retrieve Message in Parts Using SSL

Article: Q194998
Product(s): Microsoft Exchange
Version(s): WinNT:5.5
Operating System(s): 
Keyword(s): exc55sp2fix
Last Modified: 29-APR-1999

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The information in this article applies to:

- Microsoft Exchange Server, version 5.5 
-------------------------------------------------------------------------------


SYMPTOMS
========

IMAP4 customers using Netscape Messenger 4.5 enabled for Secure Socket Layer
(SSL) against an Exchange Server 5.5 IMAP4rev1 computer, might encounter message
content loss. Messages 6 KB in size or greater might be truncated (this is
regardless if messages contain attachments or not).

CAUSE
=====

Netscape Messenger 4.5 has moved to fetching messages in chunks (prior releases
of Messenger always fetched the entire message). The command Messenger now
issues to fetch a message is as follows:

  11 UID fetch 320 (UID RFC822.SIZE BODY[]<0.6144>)

When using clear text, the server will respond to the above command with exactly
6144 bytes of message data. When using SSL, Exchange Server can return more than
6144 bytes of message data. When more bytes than requested is received by
Messenger, the client logs out without retrieving any more message data. Hence,
the message is displayed truncated.

RESOLUTION
==========

To resolve this problem, obtain the latest service pack for Exchange Server
version 5.5. For more 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   5.5.2437.0
  Mdbmsg.dll   5.5.2437.0
  Netif.dll    5.5.2437.0
  Store.exe    5.5.2437.0


WORKAROUND
==========

The obvious work around is to turn off SSL with Netscape 4.5. For customers who
need to continue using SSL with Netscape Messenger 4.5, a client configuration
change can be made which will alleviate the problem.

When added to the Netscape user Pref.js file, the following line will turn off
fetching in chunks:

  user_pref("mail.imap.fetch_by_chunks", false);

Netscape Messenger 4.5 will return to fetching the entire message in one command
(as was the behavior in Netscape Messenger 4.07). Upon restarting the client,
messages that were previously truncated can be fetched again and all message
content displayed.

STATUS
======

Microsoft has confirmed this to be a problem in Microsoft Exchange Server
version 5.5. We are currently working on a fix to correct this problem.

======================================================================
Keywords          : exc55sp2fix 
Technology        : kbExchangeSearch kbExchange550 kbZNotKeyword2
Version           : WinNT:5.5
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

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