This is a fundamental misunderstanding of kerberos versus active directory's NTLM implementation.
In order for Kerberos to work you have to allow the remote computer to impersonate others in your directory, and both the requester and receiver of the kerb request must trust your directory server (domain controller) for kerb auth.
Typically you achieve this by joining both servers to your active directory, and enabling kerberos on the computer that will do the auth (your splunk server in this case).
Please work with your domain admins and oracle team to configure this properly.
