You need to set up target discovery addresses, so that the iSCSI adapter can determine which storage resource on the network is available for access.
The ESXi system supports these discovery methods:
Also known as SendTargets discovery. Each time the initiator contacts a specified iSCSI server, the initiator sends the SendTargets request to the server. The server responds by supplying a list of available targets to the initiator. The names and IP addresses of these targets appear on the Static Discovery tab. If you remove a static target added by dynamic discovery, the target might be returned to the list the next time a rescan happens, the iSCSI adapter is reset, or the host is rebooted.Note:
With software and dependent hardware iSCSI, ESXi filters target addresses based on the IP family of the iSCSI server address specified. If the address is IPv4, IPv6 addresses that might come in the SendTargets response from the iSCSI server are filtered out. When DNS names are used to specify an iSCSI server, or when the SendTargets response from the iSCSI server has DNS names, ESXi relies on the IP family of the first resolved entry from DNS lookup.
In addition to the dynamic discovery method, you can use static discovery and manually enter information for the targets. The iSCSI adapter uses a list of targets that you provide to contact and communicate with the iSCSI servers.