DOCUMENT:Q235051  30-SEP-1999  [exchange]
TITLE   :XADM: Disabling POP3 Clear Text Authentication Disables SSL CTA
PRODUCT :Microsoft Exchange
PROD/VER:winnt:5.5
OPER/SYS:
KEYWORDS:exc55 EXC55SP3Fix

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

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


SYMPTOMS
========

Administrators are given the option to choose what type of authentication
mechanism is allowed for POP3 users. If an administrator chooses to disable
clear text authentication (CTA), this also disables clear text authentication
over Secure Sockets Layer (SSL).

CAUSE
=====

If the request to authenticate comes in through SSL, the Exchange Server
information store authenticates the user, but an error message is returned to
the client because when the store begins processing the commands, it only checks
to see if clear text is disabled. If clear text is disabled, the store returns
an error. The store does not check to see if the command arrives through SSL.

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 | 2638.0  | 
+----------------------+
| Mdbmsg.dll | 2638.0  | 
+----------------------+
| Netif.dll  | 2638.0  | 
+----------------------+
| Store.exe  | 2638.0  | 
+----------------------+

NOTE: This fix requires the Directory fix from the following Microsoft Knowledge
Base article:

   Q230285 XADM:'Denial of service' Vulnerability in Store with IMAP or POP3


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:

======================================================================
Keywords          : exc55 EXC55SP3Fix 
Technology        : kbExchangeSearch kbExchange550 kbZNotKeyword2
Version           : winnt:5.5
Issue type        : kbbug
Solution Type     : kbfix

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

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