[tor-bugs] #14129 [Tor]: Assertion failure in dns.c, possibly connected to UDP DoS attack

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#14129: Assertion failure in dns.c, possibly connected to UDP DoS attack
-------------------------+-------------------------------------------------
     Reporter:  jowr     |      Owner:
         Type:  defect   |     Status:  needs_review
     Priority:  major    |  Milestone:  Tor: 0.2.6.x-final
    Component:  Tor      |    Version:  Tor: 0.2.6.1-alpha
   Resolution:           |   Keywords:  crash dos tor-relay 025-backport
Actual Points:           |  024-backport
       Points:           |  Parent ID:
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Comment (by jowr):

 Nice, thanks guys. Fast turnaround.

 And yes, I put a caching DNS server back up. I disabled it for some
 reason...

 ++ Cache Statistics ++
 [View: default]
              38506257 cache hits
              3766166 cache misses

 The UDP flood didn't directly impact tor itself, but took out DNS as a
 secondary effect due to either upstream silliness or some value of
 weirdness within the system itself. I'm more inclined to think its' the
 former than the latter.

 I've moved DNS into a caching nameserver, and am using ipv6 resolvers as
 primary targets so that IPv4 UDP silliness doesn't cause me any further
 issues.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/14129#comment:10>
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