Comment 11 for bug 417757

@ Markus's #8 comment: as I mentioned "Note that the DNS queries go over IPv4 (transport), there is no IPv6 _connectivity_ involved here.".

You also state 'so all IPv6 requests are answered by an IPv6 enabled DNS server."; well, unless you configured IPv6 DNS resolver addresses in your /etc/resolv.conf then queries will still go over IPv4 (transport), even though they are AAAA queries. AICCU only provides IPv6 connectivity (transport) it does not configure DNS resolvers though.

@ Bernard's #9 comment: most likely your livebox contains one of these broken DNS resolvers. Happens a lot that CPEs have this issue. Try the below to check this out. Configuring resolv.conf with OpenDNS or other working DNS servers (eg the ones of your ISP directly, instead of the livebox) might solve your problem. Do also please realize that this problem ALSO occurs on other platforms than Linux, eg Windows, which is what the majority of people are using; what to use is a choice of the user afterall....

To verify this, do a:
for i in `cat /etc/resolv.conf | grep ^nameserver | cut -f2 -d' '`; do dig @$i AAAA; done

This should return quite quickly, even though no AAAA records for exist yet. Now, if you have a broken resolver somewhere along the way, these requests won't return quickly (unless they are locally or on-path cached as negative).