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If you disable or do not configure this policy setting, Outlook will attempt to authenticate using the Kerberos authentication protocol. Outlook attempts to authenticate using NTLM only. Outlook attempts to authenticate using the Kerberos protocol only.- NTLM password authentication. This option is the default configuration.- Kerberos password authentication.
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If this attempt fails, Outlook attempts to authenticate using NTLM. Outlook attempts to authenticate using the Kerberos authentication protocol. If you enable this policy setting, you can choose from three different options for controlling how Outlook authenticates with Microsoft Exchange Server:- Kerberos/NTLM password authentication. NTLM authentication is supported in pre-Windows 2000 environments. The Kerberos protocol is the more secure authentication method and is supported on Windows 2000 Server and later versions.
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Note - Exchange Server supports the Kerberos authentication protocol and NTLM for authentication. This policy setting controls which authentication method Outlook uses to authenticate with Microsoft Exchange Server.
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