Before your ESXi host can discover iSCSI storage, the iSCSI initiators must be configured and authentication might have to be set up.
For software iSCSI and dependent hardware iSCSI, networking for the VMkernel must be configured. You can verify the network configuration by using the vmkping utility.
For independent hardware iSCSI, network parameters, such as IP address, subnet mask, and default gateway must be configured on the HBA.
Check and change the default initiator name if necessary.
The dynamic discovery address or static discovery address and target name of the storage system must be set. For software iSCSI and dependent hardware iSCSI, the address should be pingable using vmkping.
For CHAP authentication, enable it on the initiator and the storage system side. After authentication is enabled, it applies for all of the targets that are not yet discovered, but does not apply to targets that are already discovered. After the discovery address is set, the new targets discovered are exposed and can be used at that point.
For details on how to use the vmkping command, search the VMware Knowledge Base.