OSX and Happy Eyeballs

[Roman Mamedov]

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:

https://tools.ietf.org/html/rfc6724#section-2.1

-- 
With respect,
Roman