Disabling LM / NTLMv1 and enable NTLMV2 for Exchange 2016

Question

Hi Team,

Disabling LM / NTLMv1 and enable NTLMV2 for Exchange 2016.
Please confirm if compatibility checks have to be done for Outlook, workstation OS.

Cheers
Priya

Answer 1

Absolutely. This is not an Exchange issue as much as a Windows one.

https://learn.microsoft.com/en-us/archive/blogs/miriamxyra/stop-using-lan-manager-and-ntlmv1

Before making that change, you should gather auditing data and verify that nothing is using V1 and if so, then configure to use V2 if possible.

https://learn.microsoft.com/en-us/archive/blogs/miriamxyra/stop-using-lan-manager-and-ntlmv1#further-resources-on-auditing-and-purging-old-authentication-protocols

Answer 2

Hi,

I confirm that Exchange 2016 and the last OS and outlook version don't need NTLMv1.

Try to disable NTLMv1 and LM protocol from client mahine before disble them on domain controller.

Please mark this reply this reply as answer if it help your to fix your issue

Answer 3

HI
from below documents ,I think it is feasible.

Exchange 2016 compatibility with Network security: LAN Manager authentication level" - NTLMV2 response only
https://social.technet.microsoft.com/Forums/en-US/e5812087-e8bd-4db2-be2b-9b4650c5ebea/exchange-2016-compatibility-with-network-security-lan-manager-authentication-levelquot-ntlmv2?forum=Exch2016GD

Network security: LAN Manager authentication level
https://learn.microsoft.com/en-us/windows/security/threat-protection/security-policy-settings/network-security-lan-manager-authentication-level