I work for an ISP and we place users in a Walled Garden to allow them to Sign Up for service. The Walled Garden restricts traffic and redirects http traffic. We leak the http://captive.apple.com/ domain so an IOS via WiFi device can reach it and it appears to the device it has access to the Internet. The customer is then redirected to a payment portal where we detect who they are and provide content based on available offerings. Within the last 3-4 months something in IOS behavior changed, it now appears shortly after loading our webpage the users mobile device switches over to mobile/cellular service and the original webpage times out because they are no longer using the same IP or on the same network. Can someone describe the flow or what other urls need to be whitelisted?