[tor-bugs] #20216 [Metrics/Censorship analysis]: Iran blocking of vanilla and obfs3, 2016-08 and 2016-09

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#20216: Iran blocking of vanilla and obfs3, 2016-08 and 2016-09
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 Reporter:  dcf                          |          Owner:
     Type:  defect                       |         Status:  new
 Priority:  Medium                       |      Milestone:
Component:  Metrics/Censorship analysis  |        Version:
 Severity:  Normal                       |     Resolution:
 Keywords:  censorship block             |  Actual Points:
Parent ID:                               |         Points:
 Reviewer:                               |        Sponsor:
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Comment (by dcf):

 Replying to [comment:4 dcf]:
 > Replying to [comment:1 mrphs]:
 > > Looking at a couple of other countries, it seems obfs3 has been
 dropped for everyone at the same rate. Here's Germany and Russia for
 instance:
 > >
 > > DE: https://metrics.torproject.org/userstats-bridge-
 combined.html?start=2016-06-24&end=2016-09-22&country=de
 > >
 > > RU: https://metrics.torproject.org/userstats-bridge-
 combined.html?start=2016-06-24&end=2016-09-22&country=ru
 > >
 > > So perhaps it's not about obfs3 being blocked.
 >
 > You're right. Here's the graph of the most popular transports across all
 countries.

 [https://lists.torproject.org/pipermail/metrics-
 team/2016-September/000216.html Karsten writes] that 2016-09-02 was the
 date that [https://blog.torproject.org/blog/new-bridge-authority the new
 bridge authority Bifroest took over from Tonga], causing
 [https://metrics.torproject.org/networksize.html?start=2016-08-01&end=2016-09-22
 about 40%] of public bridges to stop reporting. If that 40% was
 disproportionately obfs3, that might help explain what we're seeing.

 I don't see how the changed bridge authority could have an effect on the
 number of ''direct'' users, so the fact that direct and obfs3 users both
 decreased on 2016-09-02 could be a coincidence. I just took "obfs3" out of
 the ticket title.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/20216#comment:6>
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