What the three tests mean
- IPv4 only: a test address with only an A record. Success means IPv4 works.
- IPv6 only: a test address with only an AAAA record. Success means your device, router and provider all route IPv6, and your DNS returns IPv6 addresses.
- Both: a test address with both records. The address that answers shows which protocol your browser prefers (browsers race both and usually favour IPv6).
Reading your IPv6 address
The first 64 bits are your network prefix, assigned by your provider. The last 64 bits identify the device. Modern systems choose those bits at random and change them regularly (privacy extensions, RFC 8981) so sites cannot follow your device from network to network.
If the last part contains ff:fe in the middle, it was built from your network card's hardware (MAC) address. That is an older method; switching on privacy extensions hides it.
If IPv6 fails
A failed IPv6 test does not mean your device lacks IPv6: every current operating system supports it. It means the path does not: the provider has not enabled it, the router has it switched off, or a VPN carries IPv4 only. Many VPNs block IPv6 on purpose so it cannot bypass the tunnel.
Questions
- Should I switch IPv6 off?
- No. Leaving IPv6 on is recommended. Switching it off rarely fixes anything today and breaks some services that expect it.
- Is IPv6 less private?
- Not with privacy extensions, which are on by default in Windows, macOS, iOS and Android. Sites see a temporary address, and the /64 prefix identifies your home network much like a shared IPv4 address does.