[p1mrx]

Here: http://test-ipv6.com/

It's not possible to determine both your IPv4 and IPv6 address in a way that's compatible with curl or links, however. You need something like JavaScript to issue the second request.

[X-Istence]

I really don't care about retrieving my IP address using curl ... it is in my browser that I care about.

Yes, test-ipv6.com works, but it is far some simple, running various other tests as well.

[p1mrx]

> test-ipv6.com works, but it is far some simple

How about http://ip6.me/ and http://ip4.me/ ?