[tor-bugs] #18828 [Core Tor/Tor]: Regenerate fallback list for 0.2.9

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#18828: Regenerate fallback list for 0.2.9
---------------------------------------------+-----------------------------
 Reporter:  teor                             |          Owner:  teor
     Type:  enhancement                      |         Status:
                                             |  needs_review
 Priority:  Medium                           |      Milestone:  Tor:
                                             |  0.2.9.x-final
Component:  Core Tor/Tor                     |        Version:
 Severity:  Normal                           |     Resolution:
 Keywords:  TorCoreTeam201612, 029-accepted  |  Actual Points:
Parent ID:  #20172                           |         Points:  3
 Reviewer:                                   |        Sponsor:  SponsorU-
                                             |  can
---------------------------------------------+-----------------------------
Changes (by teor):

 * status:  needs_revision => needs_review


Comment:

 Replying to [comment:26 teor]:
 > > * restore the 120 day stability period and 99% uptime requirement that
 were reduced in 0.2.8 due to #18050
 >
 > I initially tried 183 days stability and 99% uptime, but that excluded
 too many good relays.
 > Instead, I am switching it back to 120 days (4 months) and 98%.
 >
 > 120 days is a compromise between the 6-monthly major tor release cycle,
 and actual relay stability.
 >
 > 98% still gives us `(0.98)^3 = 94%` of clients bootstrapping in the
 first 5 seconds, before contacting an authority.
 > `8/(200*10 + 8) * 3 = 1.2%` of clients try an authority in their first 3
 attempts anyway, as the authorities are also in the fallback list (but
 with lower weight).

 We can't require this level of stability, because so many relays are being
 excluded due to the recommended versions and #20539.

 Instead, I chose 7 days and 90%, which means at least 73% of fallbacks can
 bootstrap without contacting an authority.

 We can merge the latest version of my github fallbacks-201612-* branch
 containing the script, whitelist, and blacklist to master in this ticket.

 The current draft branch used to build the list in #20170 is
 fallbacks-201612-v3 on my github:
 https://github.com/teor2345/tor/tree/fallbacks-201612-v3

 If someone likes reading python, I'd love a review.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/18828#comment:27>
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