Do you have IPv6?

IPv6 (Internet Protocol version 6) is the most recent version of the Internet Protocol. It uses 128-bit addresses (e.g. 2001:db8::1) instead of IPv4's 32-bit addresses, providing a vastly larger address space to accommodate the billions of devices now connected to the internet.

Use this page — it detects your IPv4 and IPv6 addresses automatically and shows a clear verdict. If you see an IPv6 address and a green 'IPv6 Ready' badge, your connection supports IPv6.

IPv4 uses 32-bit addresses like 192.168.1.1 and supports ~4.3 billion unique addresses, which are nearly exhausted. IPv6 uses 128-bit addresses like 2001:db8::1 and supports 340 undecillion addresses. IPv6 also has built-in support for larger packets, better routing, and improved security features.

Modern websites and services are increasingly reachable over both IPv4 and IPv6. When your system prefers IPv6, connections to dual-stack sites are made over IPv6, which is generally faster and avoids IPv4 address translation overhead. If your system prefers IPv4 even though IPv6 is available, you may benefit from checking your OS network settings.

No. The API endpoints at ipv6tool.com report the IP address of the caller — the machine making the HTTP request. They cannot test a third party's network. To test a human user's connectivity, share a link to https://ipv6tool.com/ so their browser runs the test directly. The /api/testlink endpoint returns that URL for use by AI agents.