Thanks Charly – yes.. in this case a flag or error in logging that IPv6 was not reachable would have saved me many hours of debugging (for us, this was an obscure IPv6 issue, where all other IPs on the same range work; it was broken as a function of a very restrictive ND policy on the firewall).

So regardless of Full v6 support, or v6 only support [both are needed], at the very least some good logging to say if its failing would be great 😉

From: tor-relays <tor-relays-bounces@lists.torproject.org> On Behalf Of Charly Ghislain
Sent: Thursday, April 18, 2019 2:41 PM
To: tor-relays@lists.torproject.org
Subject: [tor-relays] ipv6 behaviour consensus

Hi list,

Last reply from s7r on jake Visser' issue included a link to an open issue waiting for a consensus on a mailing list:

https://trac.torproject.org/projects/tor/ticket/29570

Not sure if teor implied the dev mailing list or this one, but maybe gathering feedback from operators is a good idea.

AFAIC, as avee stated on the ticket I don't find the current setup much confusing. The documentation on ipv6 setup was not as clear as one would expect, I came across what appeared to be outdated docs, and I think this is the area that could be improved to eases operator setup. 

I agree with Avee that any update on that matter should be backward compatible, allowing relays running behind custom natted networks to continue operating without any trouble.

I feel there is an issue in case the operator advertises an unreachable ip6 address in the config. This seems like a configuration error that should be spotted by a self-reachability mechanism that is yet to come, like for ipv4. I can imagine however that directories could be able to flag the relay as reachable over ipv4 and not over ipv6, and that the relay would still be usable over ip4. I thought it was the case actually.

Please provide your feedback. ip6 is around for so long, it is depressing to see how hard it is for so many software to provide a nice user experience with it.

Regards,

Charly