[tor-bugs] #29725 [Core Tor/sbws]: Reset relay bandwidths when their IPv6 address changes

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#29725: Reset relay bandwidths when their IPv6 address changes
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 Reporter:  juga           |          Owner:  (none)
     Type:  defect         |         Status:  new
 Priority:  Medium         |      Milestone:  sbws: 1.2.x-final
Component:  Core Tor/sbws  |        Version:  sbws: 1.0.5
 Severity:  Normal         |     Resolution:
 Keywords:  scanner        |  Actual Points:
Parent ID:  #29954         |         Points:  1
 Reviewer:                 |        Sponsor:
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Comment (by teor):

 Actually, I don't think we should make this change for IPv6, because it
 will penalise relays that use IPv6 address privacy extensions.

 IPv6 address privacy extensions make some machines change their IPv6
 address regularly. (By default, once per day, with old addresses lasting
 one week). The rest of the tor network copes well with address changes at
 that rate. (See https://tools.ietf.org/html/rfc4941#section-3.5 .)

 But if we make this change on bandwidth authorities, they will reset the
 bandwidth of relays that use IPv6 address privacy extensions, every day.
 Since sbws only measures the whole network once per day, any relay that
 uses IPv6 address privacy extensions won't get much consensus weight.

 If we don't make this change, then when relays change networks, sbws will
 take a few days to measure their new bandwidth. That's ok. Network changes
 happen a lot less often than IPv6 privacy extensions address changes.

 If sbws can ever scan the network once per hour, we could think about
 implementing this change.

 What do you think, juga? Should we close this ticket?

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/29725#comment:3>
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