I'm building a web app which sends web-push. I read this and other articles. https://developers.google.com/web/fundamentals/codelabs/push-notifications/?hl=en
I succeeded to send and receive a push in my development environment.
The problem is: we have to make outgoing request from our app server but almost every port on the app server are closed in the production environment.
We don't have a chance to know the endpoint URL until pushManager.subscribe is done. I think the URL could be changed time by time or user by user. Also it's depends on which browser is used. So we can't tell which port to open.
I tried with my Chrome and Firefox and the endpoint URLs were
https://updates.push.services.mozilla.com:443/
but are they always these ones?
Are there any official documents for host/ports to be opened on firewall for web push?