How can I disable IP forwarding from IPv6 toIPv4
Solution 1:
You can override which IP protocol stack is used with the -4 and -6 options, which restrict it to IPv4 or IPv6 respectively. Consider:
$ curl -6 http://ip4only.me/api/
curl: (6) Could not resolve host: ip4only.me
$ curl -4 http://ip4only.me/api/
IPv4,198.51.100.84,Remaining fields reserved for future use,,,