You must first discover a target before you can view its connections, sessions, and device information on the Targets tab.
Target Portals - You can discover an iSCSI target device, and then connect to the target on the Targets tab.
iSNS servers - The use of an Internet Storage Name Service (iSNS) server operates similarly to that of a Domain Name System (DNS) server. The client computer that is running iSCSI Initiator requests that the iSNS server query for iSCSI targets that are accessible to the client. Adding an iSNS server allows for the automatic discovery of iSCSI targets that are accessible to the client. Removing the iSNS server would prevent automatic discovery, and would require you to manually enter the iSCSI target name for every iSCSI target.
For a client to properly interact with an iSNS server, the iSNS server firewall exception must be enabled. This is done by allowing the iSCSI Service to communicate through the Windows firewall.