SMB NTLM blocking
Microsoft's edit ·
Microsoft's commit message in MicrosoftDocs/windowsserverdocs · commit 5d258b0 · +3 −3 lines · also on GitHub
⋯ 3 unchanged lines
44
ms.topic: how-to
55
author: Heidilohr
66
ms.author: helohr
7
−ms.date: 01/22/2024
7
+ms.date: 02/21/2024
88
ms.prod: windows-server
99
---
1010
# Block NTLM connections on SMB (preview)
1111
1212
> [!IMPORTANT]
13
−> NTLM blocking in SMB is currently in PREVIEW.
14
−> See the [Supplemental Terms of Use for Microsoft Azure Previews](https://azure.microsoft.com/support/legal/preview-supplemental-terms/) for legal terms that apply to Azure features that are in beta, preview, or otherwise not yet released into general availability.
13
+> Windows Server Insider builds are in PREVIEW.
14
+> This information relates to a prerelease product that may be substantially modified before it's released. Microsoft makes no warranties, expressed or implied, with respect to the information provided here.
1515
1616
The SMB client now supports blocking NTLM queries for remote outbound connections. Blocking NTLM queries prevents bad actors from tricking clients into sending NTLM requests to malicious servers, counteracting brute force, cracking, and pass-the-hash attacks. NTLM blocking is also required for switching an organization's authentication protocols to Kerberos, which is more secure than NTLM because it can verify server identities with its ticket system. However, organizations can also enable this layer of protection without having to disable NTLM entirely.
1717
⋯ 90 unchanged lines
Microsoft's Markdown source from MicrosoftDocs/windowsserverdocs, © Microsoft Corporation, under CC BY 4.0. Changed lines with up to 3 unchanged lines around each; ChangeIntel kept this copy 10 Oct 08:53 UTC. The commit date is when the source changed, which can be hours or days before Learn published it.