I had similar issues, but finally got it working. First you need to ensure, that your devices get a ipv6 from your router. On a fritzbox go to
Netwerk and click the pencil next to your
hassio entry. Under
IPv6-Adressen you should see some addresses. On my fritzbox every device has 2 IPv6 addresses.
One starting with
fe80 (link local) and one starting with
2.... The second one is the one you need to use.
Now create a port forwarding to your raspi. It’s important, that the port forwarding interface ID is the correct IPv6 address (the one starting with
2...). If you have multiple addresses starting with
2..., just try one after another and see if it works.
BTW feste-ip.net or an 6tunnel is only needed, if you want to access your raspi with your mobile phone. And if you are a client of Telekom, you don’t even have to do that, because they support IPv6 already. So from any desktop client you should be able to connect to your raspi even without feste-ip or 6tunnel.
Now we will test the IPv6 connection. First we need to ensure that we don’t have any
base_rul set in the
http settings, otherwise you will not have access via the plain IPv6 (later you can create a domain with a
AAAA entry pointing to your IPv6, but for testing purpose, try without). Also ensure, that you set
server_host: ::0 (although hassio tells you to not use that, it works)
Don’t forget to reboot, when you change those settings.
http entry should look like:
First step to test the IPv6 would be, to take the IPv6 address, put it in  and add the port, like:
Put this in your browser and see if you get a connection.
If you have access, your IPv6 is working.
Test this and let me know, if you have access to your hassio.