Controls how kerberos tickets are verified. Valid options are: secrets only - use only the secrets.tdb for ticket verification (default) system keytab - use only the system keytab for ticket verification dedicated keytab - use a dedicated keytab for ticket verification secrets and keytab - use the secrets.tdb first, then the system keytab The major difference between "system keytab" and "dedicated keytab" is that the latter method relies on kerberos to find the correct keytab entry instead of filtering based on expected principals. When the kerberos method is in "dedicated keytab" mode, must be set to specify the location of the keytab file. dedicated keytab file secrets only