NTLM authentication

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Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

 

NTLM authentication

In a networking environment, NTLM is used as the authentication protocol for transactions between two computers where one or both computers are running Windows NT 4.0 or earlier. Networks with this configuration are referred to as mixed-mode, the default setting in the Windows Server 2003 family.

As examples, the following configurations would use NTLM as the authentication mechanism:

  • A Windows 2000 or Windows XP Professional client authenticating to a Windows NT 4.0 domain controller.

  • A Windows NT 4.0 Workstation client authenticating to a Windows 2000 or Windows Server 2003 domain controller.

  • A Windows NT 4.0 Workstation client authenticating to a Windows NT 4.0 domain controller.

  • Users in a Windows NT 4.0 domain authenticating to a Windows 2000 or a domain running Windows Server 2003 family.

  • A client running Windows 95, Windows 98, or Windows Millennium Edition that is authenticating to any domain controller.

In addition, NTLM is the authentication protocol for computers that are not participating in a domain, such as stand-alone servers and workgroups.

For more information about NTLM and NTLMv2, see "Logon and Authentication" at the Microsoft Windows Resource Kits Web site. (https://www.microsoft.com/)