I figured it out... No, the GUI can't disable ports, but you can disable both IPV4 and IPV6 from the CLI on the unused ports. After doing this, my iSCSI discovery only returns with the correct (active) ports.
MD3200i with dual controllers.  At this point, I have the management ports connected and HIC 1, Port 0 connected/configured on both controllers. Here's my issue.... By default, the other HIC ports have private addresses on different subnets (e.g., 192.168.131.101). The controller knows these ports are disconnected, but when I do discovery (from Linux), it sends (and my Linux host tries to access) all 8 ports-- even though only two of them have valid addresses/are connected physically. From the GUI, I cannot disable both IPV4 and IPV6 on the unused ports (the OK button is not active).  Ideas?? Is this something I can/need to fix from the CLI or am I missing something?  --- Cris
MD3200i host ports and discovery (how to disable ports)