On Thu, Aug 16, 2012 at 03:04:04AM +0800, Eric S Johnson wrote: > Yes—they stopped doin packet inspection in about 2008, near as I can tell. > > > From: Steve Weis [mailto:[email protected]] > Sent: Thursday, 16 August 2012 00:56 > To: Eric S Johnson > Cc: Stanford tech list > Subject: Re: [liberationtech] Images of Blocking in Different Countries? > > > > This paper "Ignoring the Great Firewall of China" is a few years old, but at > the time China was inspecting TCP packets for verboten keywords: > > http://www.cl.cam.ac.uk/~rnc1/ignoring.pdf > > The blocking was easy to circumvent. The researchers were able to just ignore > TCP reset packets and the connections proceeded unhindered. They also were > able > to conduct a denial of service attack against IP addresses in China by > spoofing > packets with forbidden content, which would trigger spurious connection > resets. > > > > This was 6 years ago, so I'm sure the game has changed somewhat.
Eric, that's interesting, could you elaborate on that? According to my own experience, deep packet inspection in China is still used for several different purposes. A study from 2011 [1] was looking at where the filtering occurs. They used the keyword "falun" within HTTP GET requests in order to trigger filtering. Besides HTTP, deep packet inspection seems to be used for DNS [2], as you pointed out, and also to block the Tor network. After all, I believe that the main results of "Ignoring the Great Firewall of China" are, aside from a couple of details of course, still valid. Philipp [1] http://www.eecs.umich.edu/~zmao/Papers/china-censorship-pam11.pdf [2] http://conferences.sigcomm.org/sigcomm/2012/paper/ccr-paper266.pdf _______________________________________________ liberationtech mailing list [email protected] Should you need to change your subscription options, please go to: https://mailman.stanford.edu/mailman/listinfo/liberationtech If you would like to receive a daily digest, click "yes" (once you click above) next to "would you like to receive list mail batched in a daily digest?" You will need the user name and password you receive from the list moderator in monthly reminders. You may ask for a reminder here: https://mailman.stanford.edu/mailman/listinfo/liberationtech Should you need immediate assistance, please contact the list moderator. Please don't forget to follow us on http://twitter.com/#!/Liberationtech
