In the USA, POTUS can shut down the internet for up to 120 days without Congressional approval for National Security. There is also a pending bill that would allow DHS to do the same, independent of POTUS or Congress. I guess the moral is, if things get really dicey, don't think that you can rely on electronic communications like Skype or Vonage, or on the internet for information like first aid, water purification, weather, etc... I'm sure any country would do this if conditions were right. As they say, it's easier to ask forgiveness than permission.