[tor-bugs] #18456 [Tor]: Exits on 0.2.7 publicise all their IP addresses in their descriptor

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#18456: Exits on 0.2.7 publicise all their IP addresses in their descriptor
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     Reporter:  teor    |      Owner:
         Type:  defect  |     Status:  new
     Priority:  Medium  |  Milestone:  Tor: 0.2.8.x-final
    Component:  Tor     |    Version:  Tor: 0.2.7.2-alpha
     Severity:  Normal  |   Keywords:
Actual Points:          |  Parent ID:
       Points:          |    Sponsor:
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 Roger and I just spoke about the feature in 0.2.7 where Exits ban all
 their local / configured IP addresses in their descriptor.

 If processes on an Exit trust connections from the local machine, this
 prevents Exits being attacked by making a connection to their IP
 addresses.

 But it also means that all exit addresses appear in the consensus.

 Roger thinks this will surprise some Exit operators. It also makes Exit IP
 addresses easier to censor.

 That said, if we silently block connections to these IP addresses, then
 clients can scan Exits and see which addresses are refused even though
 they are not banned in the Exit policy.

 We should contact relay operators with multiple IP addresses, and see if
 they appreciate this feature, or if they are surprised by it.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/18456>
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