In a storage area network (SAN), target and initiator groups define sets of targets and initiators that can be associated with a logical unit number (LUN). A LUN that is associated with a target group is only accessible via those group's targets. A LUN that is associated with an initiator group is only accessible by those group's initiators. You apply initiator groups and target groups to a LUN when you create a LUN. LUN creation cannot be completed successfully without defining at least one target group and one initiator group.
Aside from Challenge-Handshake Authentication Protocol (CHAP) authentication, which can be selected only for iSCSI/iSER initiator access, there is no authentication performed.