Just a few days after Turkey's scandal-rocked government banned Twitter by tweaking national DNS settings, the state has doubled down by ordering ISPs to block Twitter's IP addresses, in response to the widespread dissemination of alternative DNS servers, especially Google's 22.214.171.124 and 126.96.36.199 (these numbers were even graffitied on walls).
Following the ban, Turkey's Twitter usage grew by 138 percent. Now that Twitter's IP range is blocked, more Turkish Internet users are making use of Tor and VPNs, and they continue to use SMS for access to the service.
It's interesting that Prime Minister Recep Tayyip Erdoğan has singled out Twitter for his attacks ("Twitter, schmitter! We will wipe out Twitter. I don't care what the international community says.") Why not Facebook or Google Plus? I'm not certain, but my hypothesis is that Facebook and Google's "real names" policy — which make you liable to disconnection from the service if you're caught using an alias — make them less useful for political dissidents operating in an environment in which they fear reprisals.
According to the Internet activist collective Telecomix, there also were reports that devices configured to use Google's DNS service or other DNS providers outside the country were being hijacked to a local DNS server by the Wi-Fi network at Istanbul's airport.
The move has driven up the usage of VPN services and the Tor anonymizing network in Turkey. Telecomix has been providing a list of Tor gateways for Turkish users. Tor network metrics show a huge spike in users directly connecting to the Tor network over the past few days, growing from 25,000 users to 35,000 since March 19. Downloads of VPN software have also exploded with VPN apps for Apple's iOS and Google's Android becoming the most downloaded apps from their respective app stores in Turkey.
After DNS change fails, Turkish government steps up Twitter censorship [Sean Gallagher/Ars Technica]