The NAS server uses the Challenge Handshake Authentication Protocol (CHAP) to authenticate iSCSI initiators. CHAP requires a “shared secret” known by the initiator and the target. The NAS server also supports mutual authentication where the initiator authenticates the target on the server and the server authenticates the initiator.
To facilitate the mutual authentication process, the server must maintain a list of the initiators with which it can authenticate and the shared secret for each initiator.