I have a AirPort Extreme 802.11n (5th Generation) connected to a Zyxel VMG1312-B30A modem. My ISP is Deutsche Telekom with VDSL.
For quite some time I was able to use native IPv6. But this stopped working for me and I don't know why. I am unable to set IPv6 mode on the Airport to Automatic or even Manually! I tried both Airport Utility on the Mac and iOS.
I'm getting a IPv6 Relay Error. Strange thing, with other hardware it works just fine.
Did this change with a firmware update? What can I do to get this working again?