Hi Obaid,

I'm using the Group Policy Management Console (GPMC) snap-in. I'm
configuring hardened UNC paths for \\*\NETLOGON and \\*\SYSVOL. I've
uploaded a screenshot of the GPO setting to the secure file exchange.

Regards,
Kacper

On Fri, 12 Dec 2025 at 01:32, Obaid Farooqi <[email protected]> wrote:

> Hi Kacper:
>
> How are you applying this group policy on a Samba DC? If you are doing it
> on a Windows DC, what is the UNC path that you are configuring in the group
> policy editor?
>
>
>
>
>
> Regards,
>
> Obaid Farooqi
>
> Sr. Escalation Engineer | Microsoft
>
>
>
> *From:* Kacper <[email protected]>
> *Sent:* Thursday, December 11, 2025 4:59 PM
> *To:* Obaid Farooqi <[email protected]>
> *Cc:* Microsoft Support <[email protected]>; cifs-protocol <
> [email protected]>
> *Subject:* Re: [EXTERNAL] Re: Windows 11 does not appear to apply group
> policies on logon when Hardened UNC paths are configured -
> TrackingID#2512040040010550
>
>
>
> Hi Obaid,
>
>
>
> If session setup responses are always signed I would like to understand
> why the signature verification fails when Hardened UNC Paths are configured
> with RequireMutualAuthentication=1, RequireIntegrity=1, RequirePrivacy=1
> (Computer Configuration → Administrative Templates → Network → Network
> Provider → Hardened UNC Paths) and why the signature verification succeeds
>
> 1) when Hardened UNC Paths are not configured (e.g. the gpo is left at its
> not configured setting)
>
> 2) after logon when manually refreshing group policies with gpupdate
> /force.
>
>
>
> Regards,
>
> Kacper
>
>
>
> On Thu, Dec 11, 2025, 20:34 Obaid Farooqi <[email protected]> wrote:
>
> Hi Kacper:
>
> Looking at the traces, here is what’s happening:
>
>    1. Just before sending the create request for gpt.ini, client
>    determines that it is a 3-part SPN and there fore it needs to
>    reauthenticate.
>    2. Client sends a session setup request
>    3. Server (in this case Samba DC) responds with session set up response
>    4. Session set up response is always signed. Client tries to verify
>    the signature and that fails.
>
>
>
> Please let me know if this does not answer your question.
>
>
>
> Regards,
>
> Obaid Farooqi
>
> Sr. Escalation Engineer | Microsoft
>
>
>
> *From:* Kacper <[email protected]>
> *Sent:* Wednesday, December 10, 2025 4:30 AM
> *To:* Obaid Farooqi <[email protected]>
> *Cc:* Microsoft Support <[email protected]>; cifs-protocol <
> [email protected]>
> *Subject:* Re: [EXTERNAL] Re: Windows 11 does not appear to apply group
> policies on logon when Hardened UNC paths are configured -
> TrackingID#2512040040010550
>
>
>
> Hi Obaid,
>
>
>
> I have not been able to reproduce this problem against a Windows DC. I've
> uploaded the requested t.cmd traces to the secure file exchange.
>
>
>
> Regards,
>
> Kacper
>
>
>
> On Tue, 9 Dec 2025 at 21:13, Obaid Farooqi <[email protected]> wrote:
>
> Hi Kacper:
>
> You’ll have to rename t.txt to t.cmd. Your email provider does not allow
> .cmd files.
>
>
>
> Regards,
>
> Obaid Farooqi
>
> Sr. Escalation Engineer | Microsoft
>
>
>
> *From:* Obaid Farooqi
> *Sent:* Tuesday, December 9, 2025 2:10 PM
> *To:* 'Kacper' <[email protected]>
> *Cc:* Microsoft Support <[email protected]>; 'cifs-protocol' <
> [email protected]>
> *Subject:* RE: [EXTERNAL] Re: Windows 11 does not appear to apply group
> policies on logon when Hardened UNC paths are configured -
> TrackingID#2512040040010550
>
>
>
>
>
> Hi Kacper:
>
> I want to reproduce this for Windows to Windows. Please let me know the
> exact steps and set up.
>
>
>
> Alternatively, you can collect ETW traces for me on the Windows 11 client.
> The script I have attached to this email does not survive reboot. So, if
> you can reproduce the scenario without rebooting, here are the steps.
>
>
>
>    1. Unzip and copy the file t.cmd on your windows 11 client.
>    2. Login as administrator and in a cmd (elevated), execute the
>    following command:
>    >t.cmd clion
>    3. Reproduce the scenario, which I guess will require you to log off
>    and login again (preferably as a different user)
>    4. Once you see the error in Event Viewer, repro is complete.
>    5. Open an elevated Cmd window and execute the following command:
>    >t.cmd clioff
>    6. Upload the resulting t*.cab file to the link I provided you.
>
>
>
> Regards,
>
> Obaid Farooqi
>
> Sr. Escalation Engineer | Microsoft
>
>
>
> *From:* Obaid Farooqi
> *Sent:* Monday, December 8, 2025 10:38 AM
> *To:* 'Kacper' <[email protected]>
> *Cc:* Microsoft Support <[email protected]>; cifs-protocol <
> [email protected]>
> *Subject:* RE: [EXTERNAL] Re: Windows 11 does not appear to apply group
> policies on logon when Hardened UNC paths are configured -
> TrackingID#2512040040010550
>
>
>
> Hi Kacper:
>
> Thank you for the traces. I’ll look into them and get back to you as soon
> as I have anything conceret.
>
> Regards,
>
> Obaid Farooqi
>
> Sr. Escalation Engineer | Microsoft
>
>
>
> *From:* Kacper <[email protected]>
> *Sent:* Monday, December 8, 2025 4:20 AM
> *To:* Obaid Farooqi <[email protected]>
> *Cc:* Microsoft Support <[email protected]>; cifs-protocol <
> [email protected]>
> *Subject:* [EXTERNAL] Re: Windows 11 does not appear to apply group
> policies on logon when Hardened UNC paths are configured -
> TrackingID#2512040040010550
>
>
>
> Hello Obaid,
>
>
>
> Thank you for taking over this issue. The issue occurs between a Windows
> 11 client and a Samba DC. I’ve tested the same scenario against a Windows
> DC, and it works correctly there.
> My testing was done with Windows 11 (24H2, OS version 26100.7171) and
> Samba 4.21.10. I’ve uploaded the network trace, the event log entry, and
> the auth trace.
> Manually running gpupdate /force after the user logs on works without any
> issues.
>
>
> I would like to understand why Windows fails to apply GPOs during logon when
> Hardened UNC Paths are configured and the domain controller is Samba.
>
>
>
> Regards,
>
> Kacper
>
>
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