Can someone explain to me how useless countries like UAE and KSA mange to block certain apps like Whatsapp and Viper? Doesn't it just look like data packets? I have very limited understandong of how netwroking works, so I would apprecate an explaination. How can they tell what app is being used?
They simply block data packets that are addressed to Whatsapp or Viper servers. They can do this because they control the backbone routers that connect the country to the outside world. Even if the contents of the packets are encrypted, the address still needs to be readable to allow the routers to forward it to the destination. Think about a letter in the post - you can hide the contents, but you can't hide the address.
You can use a technology called tunneling to obscure the destination of a packet. Tunneling works by establishing a secure connection to a remote server, which forwards your packets on to the wider internet. An eavesdropper can only see the secure connection between you and that server; the packets being forwarded are securely encrypted, including the address. If this tunneling server is in a foreign country, then it's outside of your government's control.
There are two problems with using tunneling. Firstly, it requires some technical sophistication to set up, so most people won't figure out how to do it. Secondly, the oppressive regime can identify and block many of the servers used to provide secure tunnels. At best this creates a cat-and-mouse game, at worst it means people being arrested for evading censorship.
I was in Dubai for a week. Most apps like Whatsapp and Viber were not working. Only a select few were working, like BBM and an app called Imo. Whatsapp works if you are messaging but it won't work of you want to make a call. I don't know if the government could manage to block one bit of an app and allow another, but I found it weird. They would sometimes just block the whole app for days snd weeks and unblock it for a bit. It was all too puzzling.
Saudi Arabia was worse. They would block almost anything on "religious" grounds. What's funny is the public flag up contents and the government blocks it. Kind of like Youtube flagging.
Very weird. Why stop people from speaking with each other? I couldn't even get a Simcard without my passport being scanned. Very odd place.
>>25443 Applications generally use a specific port number to connect to on the TCP/IP stack, which can be used as a filter on a router. So to connect to this website, you connect to a machine called britfa.gs on port 80. WhatsApp uses port numbers 5223, 5228, 4244, 5242, 443, 80 and 5222. Basic VPNs often use port 1723. Not sure what Vypr uses but there will be a defined number. All email goes over port 25. HTTPS goes over port 443.
Bad countries can use these port numbers to filter all the traffic going over their backbone routers. They can then block or redirect that traffic somewhere else.
I suspect that those regimes aren't savvy enough to reliably block a skilled user, but I wouldn't want to get caught. A business traveler or expat trying to watch iPlayer should be fine, but if I were a local I'm not sure I'd risk it.
China have successfully blocked Tor and the vast majority of commercial VPN services, but the Great Firewall is incredibly sophisticated.
>>25456 There are holes in the Golden Shit [1] too. The chance of the po-po paying you a re-educational visit for going through those holes is higher though.
[1] They call that filtering system 'Golden Shield' or something actually.
