Hey, Windows always reports some hard-coded IPv6 DNS servers that don't actually exist. I see three of them, they're all prefixed with fec0:0:0:ffff. This often doesn't hurt, but it does hurt when these rogue nameservers end up at the top of the server list, because c-ares first tries all of them before it moves on to something that does work.
Given this comment someone must have already been aware of this problem: /* NB on Windows this also returns stuff in the fec0::/10 range, seems to be hard-coded somehow. Do we need to ignore them? */ This patch makes c-ares actually ignore these rogue servers. - Bert
0001-Ignore-rogue-DNS-servers-reported-by-windows.patch
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