Subject: Non-existing DNS servers on windows

Non-existing DNS servers on windows

From: Bert Belder <>
Date: Thu, 20 Oct 2011 15:35:33 -0700


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

Received on 2011-10-21