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Q103826: User Authentication Fails on LAN Manager Client

Article: Q103826
Product(s): Microsoft Windows NT
Version(s): 3.1 4.0
Operating System(s): 
Keyword(s): kbnetwork
Last Modified: 08-AUG-2001

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The information in this article applies to:

- Microsoft Windows 3.1 
- Microsoft Windows NT Advanced Server, version 3.1 
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SYMPTOMS
========

Windows NT does not properly store passwords with extended characters in the
Microsoft LAN Manager-compatible password entry in the Security Accounts Manager
(SAM) database. This may cause your Microsoft LAN Manager, Remote Access Service
(RAS), or Macintosh clients to fail authentication if their passwords contain
extended characters.

CAUSE
=====

Each user account has two passwords, both a LAN Manager and a Windows
NT-compatible password. Each password is doubly encrypted and stored in the SAM
database. The two passwords enable Windows NT to validate your account for both
Windows NT and LAN Manager clients.

LAN Manager passwords are not case-sensitive. Before they are encrypted, they are
converted to all uppercase letters. Windows NT has no way of making an extended
character uppercase in a consistant manner due to the differences in foreign
languages and code pages. Because of this, Windows NT stores only makes
non-extended characters uppercase; it leaves extended characters alone.

Because Windows NT handles extended characters in this manner, your password may
not match up with the one stored on a LAN Manager client.

NOTE: This problem only occurs when a password is originally created from Windows
NT User Manager or during initial logon. If the password is created by using the
LAN Manager client NET PASSWORD command, it is stored properly in the Windows NT
SAM database. Also, if the password is created with PORTUAS, it should be all
right.

STATUS
======

Microsoft has confirmed this to be a problem in Windows NT and Windows NT
Advanced Server version 3.1, and Windows NT Workstation and Server versions
3.1.We are researching this problem and will post new information here in the
Microsoft Knowledge Base as it becomes available.

REFERENCES
==========

For more information on Windows NT authentication or why RAS must convert the
character case of passwords, query on the following words in the Microsoft
Knowledge Base:

  ras\sfm and password and authentication

For more information on other password authentication problems, see the Knowledge
Base article entitled, "RAS\SFM use LAN Manager Password Authentication."

For more information on Windows NT Authentication, see the Knowledge Base Article
entitled, "INF: User Authentication with Windows NT."

Additional query words: prodnt

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Keywords          : kbnetwork 
Technology        : kbWinNTsearch kbWinNTAdvSerSearch kbWinNTAdvServ310 kbWin3xSearch kbWinNT310Search kbZNotKeyword3 kbWin310
Version           : 3.1 4.0

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