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Q220965: XWEB: OWA NT Challenge Response Not Working as Expected

Article: Q220965
Product(s): Microsoft Exchange
Version(s): WINDOWS:5.5
Operating System(s): 
Keyword(s): 
Last Modified: 22-JUN-2001

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The information in this article applies to:

- Microsoft Outlook Web Access, version 5.5 
- Microsoft Outlook Web Access, version 5.5 Service Packs 1, 2, 3 
- Microsoft Exchange Server, version 5.5 
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SYMPTOMS
========

When you attempt to log onto Outlook Web Access (OWA) after installing Exchange
Server version 5.5 or an Exchange Server 5.5 service pack, you will be prompted
for credentials, even though Internet Information Server has been set to use NT
Challenge Response (NTCR) for authentication. After entering your Windows NT
credentials, OWA should function.

CAUSE
=====

NT Challenge/Response authentication is no longer enabled in the security
authentication methods for the IIS server. By default, installing Exchange OWA
on an IIS 4.0 server will enable Basic (clear text) authentication and disable
NTCR. This only occurs with IIS 4.0 installations, and not with IIS 3.0.

WORKAROUND
==========

If IIS and Exchange Server are installed on the same physical computer, you can
re-enable NT Challenge Response if you want it. If security is an issue, you may
want to consider installing Secure Sockets Layer(SSL). For more information on
enabling SSL, see the documentation for IIS version 4.0.

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products that are
listed at the beginning of this article.

Additional query words:

======================================================================
Keywords          :  
Technology        : kbOutlookSearch kbOWASearch kbOWA550 kbOWA550SP1 kbOWA550SP2 kbOWA550SP3
Version           : WINDOWS:5.5
Issue type        : kbbug
Solution Type     : kbpending

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