OSX and Happy Eyeballs

Roman Mamedov rm at romanrm.net
Wed Nov 18 08:32:13 CET 2020

On Tue, 17 Nov 2020 13:00:01 +0100
"Marco Davids (SIDN)" <marco.davids at sidn.nl> wrote:

> Hello,
> We have a Wireguard VPN and everything is working fine.
> There is just one little thing: IPv6 Happy Eyeballs.
> Without the VPN enabled, happy eyeballs works fine. The AAAA (IPv6) is 
> preferred over A (IPv4). But as soon as we enable the tunnel, it's the 
> other way around.
> IPv6-only sites are perfectly reachable, but dual-stack sites are always 
> reached over IPv4.
> It is not a showstopper, but I am just trying to understand why this is.
> Anyone with the same experience and more knowledge about the inner 
> workings of Wireguard and Apple's happy eyeballs implementation that 
> would care to comment?

Do you use ULA IPs (fc00::/7) for the tunnel endpoints? Those are always
depreferred compared to IPv4. See RFC 6724:


With respect,

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