[Cyberduck-trac] [Cyberduck] #8848: IPv6 (non link-local) should be routed by the OS

[Cyberduck]

#8848: IPv6 (non link-local) should be routed by the OS
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    Reporter:  richardvd  |      Owner:
        Type:  defect     |     Status:  new
    Priority:  normal     |  Milestone:  4.8
   Component:  core       |    Version:  Nightly Build
    Severity:  normal     |   Keywords:  IPv6, routing
Architecture:  Intel      |   Platform:  Mac OS X 10.10
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 Related to [ticket:8802 Ticket 8802].

 r17562 has fixed the 'no route to host' issue when connecting to IPv6-only
 hosts. However, the way it is currently implemented does not work for all
 cases.

 How it currently works (as I understand it): The application scans all
 network interfaces, and the first one that is not on a blacklist and seems
 IPv6-capable will be used. The problem is that the application does not
 know (and should not know) about the routing table and routing policies of
 the OS, and therefore often makes the wrong decision.

 For example, on a MacBook Air with no IPv6 interfaces other than the
 onboard Wi-Fi, r17652 correctly selects 'en0' for the IPv6 traffic. But f
 I enable Apple's BTMM (Back to My Mac), then r17652 selects 'utun0'
 although that interface doesn't provide any internet access. Result: 'no
 route to host'.

 Another example, if I hook up an Ethernet connection 'en3', it becomes the
 default gateway for IPv6 so I expect FTP traffic to go through that
 interface. However, r17652 will still select the 'en0' interface (Wi-Fi).

 To my understanding, interface selection by the user is only relevant for
 the non-routable link-local IPv6 addresses (fe80::/64), and all other
 routing decisions should be left to the OS.

 Please fix this by using the current automatic interface selection
 mechanism only for link-local IPv6 addresses where no interface name was
 appended to the address, and letting the OS do the routing for all other
 addresses.

-- 
Ticket URL: <https://trac.cyberduck.io/ticket/8848>
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