I have a IPv6 SixXS tunnel, which translates to interface "IPv6 Broker" rather than eth1. I also have freeDNS, and I found this Fix for choosing the interface. Only I can't configure it for IPv6. First added an AAAA record in freedns.
I changed the freedns to ipv4 external WAN. Then I tried to clone the config to the "IPv6 Broker" interface. Same username,pw and hostname, only IPv6 and the other interface. I cannot SAVE the config, because "The DynDNS mapping object with the name '' already exists." Well YEAH, that is the whole purpose. Just have 1 DNS name, with IPv4 and IPv6 ip-number.
If I change the IPv4 to IPv6, the system complains about "DynDNS IPv6 status is: currently unavailable IPv6", but it updated the record.
FreeDNS can handle IPv4 and IPv6 numbers with the same DNS name, only SOPHOS can not see the difference.