IP Address - The remappable (public) IP address that's assigned to the instance. If one has not been assigned to an instance, the instance does not have a public IP address. In order to assign an IP address to an instance you must have an available (unassigned) IP Address that you've previously reserved for use. Go to "IP Addresses" to reserve one.
Public IP Address - A public IP address is not automatically assigned to an instance. You must manually assign a remappable IP address.