In the Admin UI under “Authentication" it is possible to select one of 4 methods for authenticating user credentials; LOCAL, PAM, RADIUS or RADIUS. This can be done by changing the configuration key auth.module.type. This configuration key is not optional and is by default set to PAM. With LDAP and RADIUS additional settings are required to be able to authenticate users, for example which server to contact and any required shared secret code to be able to access the external authentication backend.