Receiving App Notifications from apps that are blocked by a network firewall I apologize if this is in the wrong spot but I am using a galaxy s7 edge and have noticed something odd that I am hoping someone here can answer.  I am currently on my companies wireless network which prevents apps like twitter and facebook from connecting etc.  However I still receive notifications from these apps when someone posts to my wall or follows me etc.  Is there a simple reason for this such as a poorly configured firewall?
Notifications for applications like Twitter and Facebook are sent through Google Cloud Messaging (GCM) or its later versions such as Firebase messaging. This is one of the ways that Google can reduce power usage on your phone, by channeling all of the periodic checking through GCM. Unless your firewall is blocking GCM, all such notifications will be let through the firewall. For notifications your Twitter app is not accessing Twitter servers directly; a Twitter server is leaving a message for your phone on a GCM server, and your phone is checking the GCM server and delivering that message to your Twitter app. 

When you are actively using your Twitter app, it will directly access Twitter servers, and a firewall will be able to block it. This is distinct from notifications.