DOCUMENT:Q225503  20-MAY-2002  [winnt]
TITLE   :MD-5 CHAP Authentication Does Not Work with Windows NT 4.0 SP4
PRODUCT :Microsoft Windows NT
PROD/VER:winnt:4.0 SP4
OPER/SYS:
KEYWORDS:kbWinNT4sp6fix

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The information in this article applies to:

 - Microsoft Windows NT Server version 4.0, Terminal Server Edition 
 - Microsoft Windows NT Workstation version 4.0 SP4 
 - Microsoft Windows NT Server version 4.0 SP4 
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SYMPTOMS
========

After you apply Windows NT 4.0 Service Pack 4 to your remote access server
computer, CHAP-MD5 authentication cannot be used for incoming dial-up
connections. Client computers that attempt to authenticate using CHAP-MD5 can no
longer connect to the remote access server.

CAUSE
=====

No valid CHAP challenge was being sent by the RAS computer.

RESOLUTION
==========

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or
the individual software update. For information on obtaining the latest service
pack, please go to:

 - http://www.microsoft.com/Windows/ServicePacks/

-or-

 - Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack

For information on obtaining the individual software update, contact Microsoft
Product Support Services. For a complete list of Microsoft Product Support
Services phone numbers and information on support costs, please go to the
following address on the World Wide Web:

   http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS


STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products that are
listed at the beginning of this article. This problem was first corrected in
Windows NT Server version 4.0, Terminal Server Edition Service Pack 6.

Additional query words: ras chap router Remote Access Server

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Keywords          : kbWinNT4sp6fix 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400search kbWinNT400search kbWinNTW400sp4 kbWinNTSsearch kbWinNTS400sp4 kbWinNTS400search kbNTTermServ400 kbNTTermServSearch
Version           : winnt:4.0 SP4
Hardware          : ALPHA x86
Issue type        : kbbug
Solution Type     : kbfix

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