Q235284: MPPE Keys Not Handled Correctly for a 128-Bit MS-CHAP Request
Article: Q235284
Product(s): Microsoft Windows NT
Version(s): 4.0
Operating System(s):
Keyword(s): kbWinNT4sp6fix
Last Modified: 16-MAY-2002
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The information in this article applies to:
- Microsoft Windows NT Server version 4.0, Terminal Server Edition
- Microsoft Windows NT Server version 4.0
- Microsoft Windows NT Server, Enterprise Edition version 4.0
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SYMPTOMS
========
Microsoft Point-to-Point Encryption (MPPE) keys may not be encrypted correctly
for a 128-bit Microsoft Challenge-Handshake Authentication Protocol (MS-CHAP)
request. The Microsoft Internet Authentication service (IAS) Remote
Authentication Dial-In User Service (RADIUS) server and Routing and Remote
Access Services (RRAS) correctly decrypt the MPPE keys, but do not correctly
encrypt them.
This problem occurs if a user either dials into a third-party network access
server (such as Cisco, Ascend, and so on) and uses 128-bit MS-CHAP on the
Windows NT 4.0 RADIUS server, or dials into a Windows NT 4.0 RRAS server that is
configured to be authenticated on a Microsoft Windows 2000 server.
RESOLUTION
==========
Windows NT Server or Workstation 4.0
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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
Windows NT Server 4.0, Terminal Server Edition
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To resolve this problem, obtain the latest service pack for Windows NT Server
4.0, Terminal Server Edition. For additional information, please see the
following article in the Microsoft Knowledge Base:
Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack
NOTE: Another solution is available by applying the RADIUS Roll-up hotfix
described in the following article in Microsoft Knowledge Base:
Q239864 Availability of Internet Authentication Service SP6 Rollup Hotfix
STATUS
======
Microsoft has confirmed this to be a problem in Windows NT 4.0 and Windows NT
Server 4.0, Terminal Server Edition.
This problem was first corrected in Windows NT Server 4.0 Service Pack 6 and
Windows NT Server 4.0, Terminal Server Edition Service Pack 6.
Additional query words:
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Keywords : kbWinNT4sp6fix
Technology : kbWinNTsearch kbWinNT400search kbWinNTSsearch kbWinNTSEntSearch kbWinNTSEnt400 kbWinNTS400search kbWinNTS400 kbNTTermServ400 kbNTTermServSearch
Version : :4.0
Hardware : x86
Issue type : kbbug
Solution Type : kbfix
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