Hello,
my device is RB951Ui-2nd.
I have a large conference hall with free wifi and anyone invited, but my network is configured to block web access, such as any web http sites and some https except my own domain 
At this point is fine, but certain apps installed onto iPads, iPhones or any android, like facebook, whatsapp, viber, iMessages, etc. is working.
Notification, sendind, receiving is passing through my firewall.
Any ideea how to block those apps?
Kind regards.