Your storage system supports three types of authentication: UNIX authentication, Windows workgroup authentication, and Kerberos authentication.
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About UNIX authentication
Using UNIX mode, authentication is performed using entries in the /etc/passwd file and/or using NIS/LDAP-based authentication.
Kerberos authentication for CIFS
With Kerberos authentication, upon connection to your storage system, the client negotiates the highest possible security level. However, if the client cannot use Kerberos authentication, Microsoft NTLM or NTLM V2 is used to authenticate with the storage system.