LmCompatibilityLevel Setting Causes POP3/IMAP User Authentication Not to Work

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Article ID: 274359 - View products that this article applies to.
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POP3/IMAP clients are not authenticated correctly if your Microsoft Exchange-based server (which is also a domain controller) is configured to use NTLM version 2 authentication and the LmCompatibilityLevel setting is set to 5.


When the LogonUser function is called with LOGON32_LOGON_NETWORK, the function does not work if the LmCompatibilityLevel setting is set to 5.

Setting the LmCompatibilityLevel setting to anything other than 5 works correctly.


To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
260910 How to Obtain the Latest Windows 2000 Service Pack
The English version of this fix should have the following file attributes or later:
   Date        Time       Version        Size     File name
   01/25/2001  03:24 PM   5.0.2195.2842  130,320  Adsldpc.dll
   01/25/2001  03:24 PM   5.0.2195.2835  348,944  Advapi32.dll
   01/25/2001  03:23 PM   5.0.2195.2816  502,032  Instlsa5.dll
   01/25/2001  03:24 PM   5.0.2195.2842  140,560  Kdcsvc.dll
   01/17/2001  02:17 PM   5.0.2195.2842  198,928  Kerberos.dll
   12/19/2000  10:13 PM   5.0.2195.2808   69,456  Ksecdd.sys
   01/25/2001  03:24 PM   5.0.2195.2816  484,112  Lsasrv.dll
   01/02/2001  09:45 AM   5.0.2195.2816   33,552  Lsass.exe
   01/23/2001  06:06 PM   5.0.2195.2850  108,816  Msv1_0.dll
   01/25/2001  03:24 PM   5.0.2195.2844  912,656  Ntdsa.dll
   01/25/2001  03:24 PM   5.0.2195.2780  363,280  Samsrv.dll
   01/25/2001  03:24 PM   5.0.2195.2797  128,272  Wldap32.dll


Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows 2000 Service Pack 2.


For additional information about how to install Windows 2000 and Windows 2000 hotfixes at the same time, click the article number below to view the article in the Microsoft Knowledge Base:
249149 Installing Microsoft Windows 2000 and Windows 2000 Hotfixes


Article ID: 274359 - Last Review: October 21, 2013 - Revision: 3.3
  • Microsoft Windows 2000 Server
  • Microsoft Windows 2000 Advanced Server
  • Microsoft Windows 2000 Professional Edition
kbnosurvey kbarchive kbhotfixserver kbqfe kbbug kbfix kbqfe KB274359

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