We're in the process of setting up our first ever Windows Failover Cluster using 2 Dell MD2600f SANs.  The volumes are connected OK and appear in Disk Manager as expected and once assigned a drive letter (and formatted to NTFS) they have been successfully added to the Cluster Manager as CSVs (Cluster Shared Volumes) so 'Volume1' and 'Volume2' appear in the C:\ClusterStorage folder (like they should).

Then I installed our firewall software (Panda Adaptive Defence 360) and at that point the volumes become inaccessible and if you try to access them, File Explorer just freezes and then crashes.  If I turn the FireWall off, then access to the 2 volumes on the SANs is regained and the mounted volumes work normally.

I've run all sorts of diagnostic software with Panda/Watchguard support to no avail.

There must be some software  or a service (or something) that is running to communicate with the mounted SAN volumes that I need to allow through our Firewall - any ideas what I might need to unblock?