IPV6 address support on exit nodes

Jeroen Massar jeroen at unfix.org
Sun Feb 6 10:15:42 UTC 2011

On 2011-02-04 16:41, Paulo Roberto wrote:
> Hi,
> My name is Beto and I'm an undergraduate student and I wish to do my
> course's final project based on Tor. I have interest in work with the
> session g of "Other conding and Design Ideas" of the volunteer page.
> Add IPV6 support for destination address on exit nodes. I had some
> Unix Programming and network skills.
> I would like some directions where to start and to know what you
> really expect in the end.

Note that I am running a private testbed of Tor nodes that support IPv6
already for bridge, relay and exit functionality.

Currently I am focusing on getting the consensus part to only tell nodes
to start using IPv6 when a certain ratio of nodes have IPv6 support
available. Bridge functionality is thus always enabled in the network so
that other nodes can come in over IPv6, but relay/exit is not enabled
yet if there are not enough nodes otherwise the ones running the few
IPv6 nodes would control everything.

Another issue is what to do with hostnames, connect over IPv4 or IPv6,
or, what the current implementation does, try AAAA's first and then A's,
as one is supposed to according to the IETF.

I also need to add a little "does IPv6 actually work" check to it,
though that is more a general system thing. This, because it could avoid
a lot of timeouts if some host thinks it has IPv6 connectivity (or IPv4
for that matter) but it actually does not work or times out.

Hopefully I will be able to invest a bit more time on this work in the
coming week and come up with a beta patch for other people to try and
then join my test network so that it can all be tested on a larger
scale. (The test network is not using the real tor network and thus
changes to the code work without affecting the live network ;)
Work is busy though, thus that is holding me off for a bit.


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