The ExtremeGuest appliance would provide all of the services you need for the captive portal. Obviously you would need to appropriately configure the guest WLAN on your RFS4000. Prior to WiNG 5.9.2. ExtremeGuest was installed on a VX9000 platform, but has now been separated out to a stand-alone VM installation. I will look for some documentation for you separately ASAP. Many thanks, Darrel.