XWEB: Outlook Web Access NT Challenge Response Not Working as Expected (220965)


The information in this article applies to:

  • Microsoft Outlook Web Access 5.5
  • Microsoft Outlook Web Access 5.5 SP 1
  • Microsoft Outlook Web Access 5.5 SP 2
  • Microsoft Outlook Web Access 5.5 SP 3
  • Microsoft Exchange Server 5.5
This article was previously published under Q220965

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 that this is a problem in the Microsoft products that are listed at the beginning of this article.
Modification Type:MinorLast Reviewed:4/28/2005
Keywords:kbbug kbpending KB220965
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