I have a Windows 7 laptop that always shows (and initially attempts to use) a pair of IPv6 addresses for DNS servers that, according to "netsh interface ipv6 show dns" are configured through DHCP:
Configuration for interface "Wireless Network Connection"
DNS servers configured through DHCP: 2001:558:feed::2
2001:558:feed::1
Register with which suffix: Primary only
The problem is that these addresses are NOT being provided on my local network and are invalid because my router has IPv6 disabled. I ran a packet trace at the time the interface is enabled to confirm that nothing is responding to the IPv6 DHCP request, only to the IPv4 request.
If I try to delete these servers using netsh I'm told that I cannot do so because they are not static.
If I plug in my Ethernet interface to the same local area network, I do not get these rogue addresses, only the expected IPv4 address.
If you look up these addresses they are owned by Comcast. Comcast is not my ISP, so I suspect they were picked up at some time in the past when I was connected to a Comcast provided network.
Because these address are first used to attempt to resolve DNS requests, initial DNS requests sometimes take a while to timeout before moving on to the valid IPv4 DNS server that IPv4 DHCP provides to the client.
How do I get rid of these rogue, "dynamic" DNS server addresses?