Android application firewall - interactive prompt confirmation for connections
I'd certainly like to see something like this, the best I could find so far was XPrivacy (root required) which you can setup to restrict Internet connections. However unless you apply a global template (license purchase required for batch apply) this is per app. Though maybe you can manipulate the system Internet process, I haven't investigated upon that so far (it's an expert setting with a very RED background, I don't want to mess up my system too much...). Though I'd certainly love to restrict tethering such that a connected Windows Laptop won't waste my data quota for updates...