There are ways to set up clandestine connections of computers, that can connect to the broader internet in a variety of ways. It was designed by the USG in fact, for use in countries they wanted to overthrow. They removed most of the information from finding it on a search page long back, but it includes beaming signals from computer to computer with bluetooth type stuff, the tor and onion routers were part of the projects, sending internet traffic over power lines, and all sorts of stuff. I read about this in detail on a dailykos journal of all places 15 years back or so. Can't find it now. There was a lot more to it.