We recently took over a domain controller and an Exchange Server, both Windows 2008 R2, with e-mail connectivity problems. We soon found invalid AAAA records in DNS. They were pointing to the IPv6 addresses of the hosts' 6TO4 tunnel adapters, not to the addresses of their physical LAN adapters.
We then deleted the wrong AAAA records on the domain controller's DNS server only to see them re-appear again within a couple of hours, breaking Exchange communication again. Who/what keeps registering these records? How do we keep them off?
("Register in DNS" in LAN connection properties is unchecked; all servers are IPv6-autoconfiguring.)