I use an advanced Firewall (Sophos UTM) to secure my networks at home.
Since the support for google assistant is available, I have the need to use myopenhab.org
To reduce the risk, I only like to open the necessary Ports to defined IP’s or DNS records.
Does anybody know, which Ports are used (incoming and outgoing) to which official IP adresses or DNS records?
I’m pretty certain that myopenhab.org only requires port 443 for https traffic and it is only outgoing. You do not need to open an incoming port. In other words, if you can bring up https://myopenhab.org in your browser, the cloud connector will be able to connect and proxy OH’s REST API.
The whole point of myopenhab.org and the cloud connector binding is that you should not have to open any ports in your firewall beyond the usual outgoing initiated HTTP/HTTPS traffic.
You can do an whois on the myopenhab.org domain for the IP addresses.