| > I have a friend who did similar tunneling a while ago. It also works on cruise ships. Hah I was just about to say the same thing! I just got home from a ~3 week cruise. Internet on the ship was absurdly expensive ($50/day). And its weird - they have wifi and a phone app that works over the internet even if you don't pay. Google maps seemed to work. And my phone could receive notifications from apple just fine. But that was about it. I spend some time staring at wireshark traces. It looks like every TCP connection is allowed to send and receive a couple packets normally. Then they take a close look at those packets to see if the connection should be allowed or blocked & reset. I'm not sure about other protocols, but for TLS, they look for a ClientHello. If preset, the domain is checked to see if its on a whitelist. Anything on their whitelist is allowed even if you aren't paying for internet. Whitelisted domains include the website of the cruise company and a few countries' visa offices. The cruise app works by whitelisting the company's own domain name. (Though I'm still not sure how my phone was getting notifications.) They clearly know about the problem. There's some tools that make it easy to work around a block like this. But the websites for those tools are themselves blocked, even if you pay for internet. :) If you figure out how to take advantage of this loophole, please don't abuse it too much or advertise the workaround. If it gets too well known or widely abused, they'll need to plug this little hole. And that would be a great pity indeed. |