Our domain controller hosts approximately 20 client pcs. One of our users is unable to log onto most, but not all, secure web sites. An ipconfig /all shows 2 dns server addresses, the first being an ipv6 type address, the second an ipv4 type. The ipv4 address is correct. All of the other client computers checked have only the one ipv4 dns address listed. The domain controller has only the one ipv4 address entered for the dns server. The computer in question operating system is Vista professional. What can be done to eliminate the spurious ipv6 dns address?