Re: [net-next 1/2] ip6_tunnel: put ip6tnl0 FB device into 'any' mode

From: "Alexey Andriyanov" <redacted>
Date: Tue, 21 Oct 2014 12:11:27 +0400

The fallback device is in ipv6 mode by default.
The mode can not be changed in runtime, so there
is no way to decapsulate ip4in6 packets coming from
various sources without creating the specific tunnel
ifaces for each peer.

Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Alexey Andriyanov <redacted>

I don't think you can legitimately change this after all
these years.  You'll break someone's setup somehow.

You're going to have to find a way to achieve what you
want whilst keeping the default unchanged.

Sorry.