In effect, all outbound traffic from this Windows 10 VM is now disabled (unless specifically allowed with a firewall rule). The default action for Windows Defender Firewall is to block traffic that doesn’t match a rule.

It’s a long list of specific rules that allow traffic out from the VM. I then went to Windows Defender Firewall and reviewed the outbound rules: It isn’t domain-joined, and I didn’t configure it beyond bypassing my Pi-Hole filtering in my home network (by pointing to Cloudflare’s 1.1.1.1 solution). Once it was ready, I patched it with the latest Cumulative updates and Feature updates. In preparation, I provisioned a fresh Windows 10 Pro virtual machine. Someone asked me this question a few months ago, and I wanted to test what happens and how a company can block all traffic except Azure’s necessary traffic.

If you block and deny all traffic in your firewall, you cannot access any Azure services. Thanks for reading my blog! If you have any questions or need a second opinion with anything Microsoft Azure, security or Power Platform related, don't hesitate to contact me.

Malwarebytes firewall