I have a windows 2008 system and it always keep ::1 in first of the dns setting.
I can see the following in "ipconfig /all":
DNS Servers . . . . . . . . . . . . : ::1 18.104.22.168 22.214.171.124
and "Obtain dns server address automatically" option in network interface setting is disabled.
I installed active directory once and uninstalled now, I think it's the reason.
But I can't find any answer from google or bing how to fix.