Use SureFox browser (Android version) to allow only certain websites. Access to any unapproved websites are blocked by the browser. There isn't even an address bar. You have to per-configure everything before the users can use the tablet. No need to mess with the network configuration.
http://www.42gears.com/surefox/
Also look at SureLock to allow only SureFox as the allowed application. Users can't access any other applications or System Settings.
http://www.42gears.com/surelock/
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Use SureFox browser (Android version) to allow only certain websites. Access to any unapproved websites are blocked by the browser. There isn't even an address bar. You have to per-configure everything before the users can use the tablet. No need to mess with the network configuration. http://www.42gears.com/surefox/ Also look at SureLock to allow only SureFox as the allowed application. Users can't access any other applications or System Settings. http://www.42gears.com/surelock/