How this IPv6 test works
Your browser asks two test hosts for its address: api4.ipify.org, which has only an IPv4 address, and api6.ipify.org, which has only an IPv6 address. If the IPv6 host answers, your connection can reach IPv6 sites. Each probe gives up after 5 seconds.
The preferred protocol is the version your browser used to load this page. Our site has both IPv4 and IPv6 addresses, so the browser picks one, and modern browsers pick IPv6 when it works.
The result is for this browser on this network at this moment. A server, a phone on mobile data or a proxy can give a different answer. Many devices also change their IPv6 address every day or so for privacy.
What is IPv6?
IPv6 is the newer version of the Internet Protocol. Its addresses are 128 bits long, so there are enough for every device to have its own public address. It runs alongside IPv4, the older version, on most networks today.
IPv4 has about 4.3 billion addresses, which ran out years ago. Providers now share IPv4 addresses between many customers. IPv6 removes that shortage, and most large providers, mobile networks and websites support it.
IPv4 vs IPv6
| Property | IPv4 | IPv6 |
|---|---|---|
| Address length | 32 bits | 128 bits |
| Written as | Four numbers from 0 to 255: 203.0.113.42 | Eight groups of hex digits, zeros shortened: 2001:db8::42 |
| Number of addresses | About 4.3 billion | About 3.4 × 10^38 |
| Sharing | Often shared through NAT | Usually one or more public addresses per device |
| DNS record | A | AAAA |
| Setup | Usually DHCP | Usually automatic (SLAAC) or DHCPv6 |
Why your IPv6 test fails, and how to fix it
"IPv4 only" means the IPv6 test host did not answer. The usual causes:
- Your provider does not offer IPv6 on your plan, or not in your area.
- IPv6 is switched off in your router.
- IPv6 is switched off on your device or network adapter.
- A firewall on an office, school or public network drops IPv6.
- A browser extension or content blocker stops requests to the test host.
- The third-party test host is slow or down for a moment.
- Run the test again. Reload this page, and try a private window with extensions off.
- Check your router. Open its admin page and look for an IPv6 setting on the internet (WAN) and local (LAN) side. Turn it on, often as "Native" or "Auto", and restart the router.
- Check your device. On Windows, make sure Internet Protocol Version 6 is ticked in the adapter properties. On a Mac, set Configure IPv6 to Automatically in the network details.
- Ask your provider. If the router shows no IPv6 address on the internet side, your provider has not enabled it for you.
Does a website support IPv6?
A site supports IPv6 when its domain has an AAAA record, the DNS record that holds an IPv6 address. If dig or nslookup returns one or more IPv6 addresses, the site can be reached over IPv6. No AAAA record means IPv4 only.
An AAAA record shows the site is published over IPv6. To confirm it answers, request it over IPv6 with curl -6 from a machine that has IPv6.
# Does the domain have an IPv6 address? dig AAAA example.com +short nslookup -type=AAAA example.com # Does it answer over IPv6? curl -6 -I https://example.com
Using IPv6 proxies
IPv6 proxies give you many addresses at a low price per IP, but they only reach sites that have IPv6. Before you buy, check your target sites for an AAAA record as shown above.
Each order is HTTPS or SOCKS5, chosen at checkout, and starts at 10 IPs.
See IPv6 proxy plans and prices →
Test IPv6 from the command line
curl -6 forces IPv6 and curl -4 forces IPv4. If the IPv6 command prints an address, the machine has working IPv6. If it fails with "Could not resolve host" or "Network is unreachable", it does not.
# IPv6 and IPv4 addresses of this machine curl -6 https://api6.ipify.org curl -4 https://api4.ipify.org # The same through our endpoint curl -6 https://t7proxy.com/ip curl -4 https://t7proxy.com/ip
