Apple Devices - Allowing access

I have seen in another thread it is recommended to allow the following so that apple devices will get the hotspot login page without needing to reboot the router.

Can someone please tell me where to implement this:

To implement a Wi-Fi popup login page:
1.DNS request for http://www.apple.com must not fail
2.HTTP request for http://www.apple.com/library/test/success.html with special user agent CaptiveNetworkSupport/1.0 wispr must not return Success.