differences in the authentication scheme - could it be because of Kerberos?

Question

I am using this script to check the connections to my sql server:

select
C.client_net_address,
S.host_name,
 c.session_id,
 c.net_transport,
 c.protocol_type,
 c.auth_scheme,
 s.program_name
from sys.dm_exec_connections c
inner join sys.dm_exec_sessions s
on c.session_id = s.session_id;

I have noticed that our servers in the UK are generally different to the servers in the US.

US:

UK:

I have found a very interesting link:

Kerberos Authentication requires that you have Service Principal Names registered

and I was wondering if that could be the case for the differences in the authentication scheme on the pictures above.

Answer 1

When the auth_scheme is SQL, that means the user is using SQL authentication, which does not, and cannot use Kerboros.

When a user that is using Windows authentication connects, authentication will first try to use Kerberos. If Kerberos fails for some reason, authentication will fall back to NTLM. Probably the most common cause of Kerberos failure is that the correct SPNs are not present in Active Directory (see Register a Service Principal Name for Kerberos Connections.