2.02, 2.10, 3.00, 3.02 : negotiate a specific version.
Default is to negotiate any SMB2 or SMB3 version.
seal : Enable SMB3 encryption.
+ sign : Require SMB2/3 signing.
NOTE:-
When using krb5cc mode use smb2_set_domain() and smb2_set_password() in the examples and applications