If the IPv6 only test shows "Server not found" or similar error or search page then you do not have working IPv6 connectivity. "Normal Test" shows which protocol your browser preferrs when you have both IPv4 and IPv6 connectivity.
You can access this page with any of these easy to remember url's:
ip4.me - IPv4 only
ip6.me - Dual stack IPv6 and IPv4 (preference depends on your
OS/client)
ip6only.me - IPv6 only
whatismyv6.com - Dual stack IPv6 and IPv4 (preference
depends on your OS/client)
For automated queries use /api/ on any of the urls for a simple plain text csv result that
will not be affected by future html changes on the main page.
Recommended API urls
(Don't forget the trailing slash to avoid unnessary 301 redirects):
ip4only.me/api/ - IPv4 only query
ip6.me/api/ - Dual stack IPv6 and IPv4 (preference depends
on your OS/client)
ip6only.me/api/ - IPv6 only test
See API v1.1 documentation for more information.