Hello,
I heard a rumour that Google is tightening up checks on the reverse
DNS of IPv6 addresses:
http://list.waikato.ac.nz/pipermail/nznog/2013-September/020066.html
I've no idea if that is the case, but given that BitFolk VPSes do
have IPv6 connectivity by default but do *not* have reverse DNS by
default, it may be worth checking your setup.
Cheers,
Andy
--
http://bitfolk.com/ -- No-nonsense VPS hosting