[tor-relays] Improving Relay IPv6 - RIPE Grant

[Ralph Seichter]

* NOC:

> I see a great benefit here, you could default to IPv6 for everything
> and enable IPv4 only as fallback [...]

Preferring IPv6 over IPv4 is not even remotely the same as your original
call to "lets drop all IPv4 only relays from consensus 2020 finally", as
you wrote in message <08fee42f-f45d-a8c4-d4e6-c83c05b4fb08 at afo-tm.org>.

Dropping support for IPv4 nodes would be counterproductive and is not
going to happen in the forseeable future, as was clarified here before
by teor.

-Ralph