I'm trying to solve some mystery in two of my environments. Both are SQL 2019 deployments, however one has Kerberos configured (i.e. SPNs are registered for the instance and port), while the other deployment does not. I've been trying to investigate how this happened but not got to the bottom of it yet.

Basically, I would like to understand the requirement for future deployments. Am I supposed to manually create (or request to be created) the SPNs or there is some way in which they get automatically created? For example, could they have been created in the course of building the application tier?

I'd appreciate if anyone is able to throw some light on this for me please. Of course I have been researching all about Kerberos authentication and SPNs but if there are any specific articles on this specific question, I'd appreciate a link to it please.

Thank you

1 Answer 1


In what circumstances do SPNs get created automatically?

As discussed in Register a Service Principal Name for Kerberos Connections - Automatic SPN Registration, the SQL Server instance will attempt to register the appropriate SPNs at startup (e.g. whenever the SQL Server service is started in Windows):

When an instance of the SQL Server Database Engine starts, SQL Server tries to register the SPN for the SQL Server service. When the instance is stopped, SQL Server tries to unregister the SPN.

  • 1
    @JD thank you so much for your helpful response. Although I still have not got to the bottom of what happened to the first instance, how it got Kerberos configured, I am nonetheless proceeding with the second instance. The instance service account has now been given elevated permissions in AD to be able to create SPNs. I then restarted the service but have not yet got a record of successful SPN registration. I guess it will take time for the settings to be effective, so I'll try again in the morning. Thanks again for always being helpful, very much appreciated.
    – PTL_SQL
    Jan 12, 2023 at 0:21
  • @PTL_SQL Glad to be of help! 🙂
    – J.D.
    Jan 12, 2023 at 0:32

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