There has been quite the talk about captive portals and the like. There is a nice setup for this called "YFi hotspot manager" previously called HotCakes. This is quite the application to run on the DMZ port for untangle, instead of having to have another box for a captive portal/hotspot managment system.

I may try to see about putting this in outside the untangle Control Panel, to see how feasible it would be.

Just my