[tor-bugs] #20071 [Core Tor/Tor]: Tor clients need 4 routers when connecting via IPv6, but only 3 using IPv4

[Tor Bug Tracker & Wiki]

#20071: Tor clients need 4 routers when connecting via IPv6, but only 3 using IPv4
------------------------------+---------------------------
     Reporter:  teor          |      Owner:
         Type:  defect        |     Status:  new
     Priority:  Low           |  Milestone:
    Component:  Core Tor/Tor  |    Version:
     Severity:  Minor         |   Keywords:  testing, ipv6
Actual Points:                |  Parent ID:  #19989
       Points:  2             |   Reviewer:
      Sponsor:                |
------------------------------+---------------------------
 The minimum number of routers in an IPv4-only Tor network is 3. But when a
 client is using IPv6, that goes up to 4, with the following log message:
 {{{
 Sep 06 13:27:47.000 [info] new_route_len: Not enough acceptable routers
 (3/4). Discarding this circuit.
 }}}

 Why is one router considered unacceptable? Is this another instance of
 #19989? (One of these routers is an exit.)

 This can be tested using chuntney's client-ipv6-only network.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/20071>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online