How to Read Dual-Stack Test Results
IPv4 and IPv6 are tested independently against protocol-specific public probes. A protocol is marked available only when this browser actually reaches its probe and the probe returns the public source address it observed.
Dual stack means both paths succeeded, but the addresses, ASN, region, response time, gateway, and route can still differ. IPv4-only and IPv6-only results describe this browser test now; they do not prove every application or destination behaves the same way.
Why IPv6 May Be Unavailable
The ISP may not provide a global IPv6 prefix, the router may not advertise it correctly, or a firewall, VPN, proxy, operating-system policy, browser extension, or temporary probe failure may block the path. A link-local address alone does not establish public IPv6 connectivity.
Retry the failed protocol first, then check the router WAN prefix and gateway, prefix delegation, RA or DHCPv6, outbound firewall rules, and tunnels that may take over only IPv4. Change one layer at a time and retest it independently.
Treat reachability and metadata as separate evidence
Network metadata is requested only after a probe returns a valid public address. If metadata fails, the confirmed connectivity result remains available instead of being overwritten by an enrichment error.
Different IPv4 and IPv6 exits are common and do not by themselves prove a privacy leak. When route consistency matters, compare DNS, WebRTC, VPN, and proxy configuration in addition to the two public network paths.