> Is there mobile push technology which is actually fundamentally push, all the way down to the transport layer? Like open socket, listening for incoming packet

> Is there mobile push technology which is actually fundamentally push, all the way down to the transport layer? Like open socket, listening for incoming packets only, no notifications-> no traffic? That’s the end-to-end principle. Each host on the Internet is fully capable of listening on a socket and doing whatever its owner wants it to do. The issue is when firewalls prevent incoming traffic, and when NAT prevents a host from even being on the internet. There’s not really a good reason for NAT with IPv6, but there are some good reasons for firewalls. They mostly boil down to human imperfection. The developers of one’s OS and software are imperfect, so the fact that a laptop sitting in Dallas can be probed by other computers in Frankfurt or Maseru thousands of times a second is an issue: a single bug will make one’s computer, and all its data, vulnerable. And users are imperfect, too. One might misconfigure one’s computer, and accidentally expose a service to the world. There could be some approaches to mitigate these issues, but we’re probably stuck with firewalls forever. Which is really kind of sad.