Hyperv connection in Veeam Linux appliance LAB isn't working

[BostjanUNIJA]

Hi.
I am building a lab environment with different scenarios.
I have virtual machines:

VM1: Veeam as linux appliance (latest version)
VM2: Veeam 12 upgraded to Veeam 13 latest version (on Windows Server STD 2025).
VM3: Hyper-v (Server 2025 std)

With Veeam13 (on windows) I am sucessfully able to add Hyper-v standalone server, by putting servername, and then credentials: HYPERV\Administrator
The same thing doesn't go thru on Veeam Linux appliance.
All servers are in same network (no firewall between; and Windows firewall on Hyperv is turned off).
I am able to ping (from Linux appliance) the servername: HYPERV successfully over shell.
The error that I receive on Linux Applliance:
Error

Cannot find the specified domain. Ensure Kerberos credentials are specified in FQDN\USER or USER@FQDN format. Local user accounts are not supported. Samba failed with error: NT_STATUS_NO_SUCH_DOMAIN [stdout: session setup failed: NT_STATUS_NO_SUCH_DOMAIN. stderr: Kinit for administrator@HYPERV to access hyperv failed: Cannot find KDC for requested realm.]

I have even tried different combination of username:
hyperv\administrator
.\administrator
administrator@hyperv.local
administrator@hyperv

But none of it works.

Also added registry key on Hyperv side and rebooted the VM did not help:
HKEY_LOCAL_MACHINE-Software-Microsoft-Windows-CurrentVersion-Policies-System
LocalAccountTokenFilterPolicy 1

There must be some 'dumb thing/solution'

F1 please anyone?

With best regards

[Mildur]

Hi Bostjan,

As the error message indicates, you need to ensure that Kerberos authentication is working correctly between the backup server and the Hyper-V host.

If you’re using a Linux-based Veeam Backup Server, you can alternatively add the Hyper-V host using the new Deployment Kit option (recommended), which enables passwordless authentication for the deployed agent.
Please use a dedicated Hyper-V Host for each deployment (Windows and Linux backup server). Machines connected by Deployment Kit cannot be shared between two backup server.

If the Deployment Kit also fails, please open a case with our Customer Support team so we can review logs and troubleshoot properly.

Best,
Fabian

[BostjanUNIJA]

HI.
Thank you for your reply.
Why does this work on VBR 13 Windows with no hussle?

[Mildur]

Backup Server on Windows still has NTLM support, which is not the case for the Backup Server on our Software Appliance.

Please see my colleague Egor’s answer here.

Best,
Fabian

[BostjanUNIJA]

Thanks again for the reply.
I like the deployment kit approach (wasn't aware of it; every day something new).
It works now. I have also read the Egor's thread.
All good.
Thanks #thumbsup