NTLM Authentication must be set to No Minimum

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Letztes Änderungsdatum des Themas: 2016-12-08

Issue: The default security setting on Windows Server 2008 R2 and Windows Server 2012 operating systems for NTLM SSP requires 128-bit encryption. If Lync client is being used on a computer not set to use 128-but encryption, users will be unable to join online meetings. The client computer must have NTLM Authentication set to No Minimum to successfully join meetings.

Description of the Issue

Depending on the client operating system mix in the enterprise, you may have to reduce this setting on a Windows Server 2008 R2 or Windows Server 2012 operating systems that are running Lync Server as a down level operating system.

For a Windows 7 operating system, the default value is set to "Requires 128-bit encryption."

For more information about the “Changes in NTLM Authentication” as it applies to Windows 2008 R2 and Windows 7 operating systems, please see Learn more about the changes in NTLM Authentication.

Issue Resolution

If you want to change the NTLM setting, follow these steps:

  • Start secpol.msc on a server running Windows Server 2008 R2, Windows Server 2012, or Windows Server 2012 R2.

  • Click to select Local Policies and then click Security Options node.

  • Make sure that the following values of the policies are set to "No Minimum."

    Network Security: Minimum session security for NTLM SSP based (including secure RPC)

    Network Security: Minimum session security for NTLM SSP based (including secure RPC) servers

For more information about the operating systems that are currently supported for Lync Server 2013, see Unterstützte Hardware für Lync Server 2013.