IPv6 Test

Introduction

The DeviceHub IPv6 Test is a free online dual-stack reachability check that probes whether your browser can reach IPv4 and IPv6-oriented echo endpoints, typically api.ipify.org for IPv4 and api64.ipify.org for dual-stack behavior, without installing OS network utilities or router admin apps. Home users wondering if their ISP finally enabled IPv6, IT staff validating dual-stack laptops before a migration, VPN customers checking whether tunnels carry v6, educators demonstrating Happy Eyeballs behavior, and developers reproducing “works on IPv4-only CI” bugs all get a fast browser answer. DeviceHub is honest: IPv6 depends on a working dual-stack path and on what echo endpoints return; api64 may still answer with IPv4 when v6 is unavailable, and success here does not certify every hostname on the internet has an AAAA record. Pair with IP Address for DeviceHub Cloudflare client-ip context, DNS Privacy Check when resolver privacy sits beside connectivity, WebRTC Leak Test when candidate families matter, and Connection Information for coarse Network Information hints that never replace real echo tests. Captive portal venues often break AAAA paths until login completes, retest after authentication. Enterprise IPv6 is sometimes disabled by policy even when the ISP offers it, unsupported results can be intentional. Mobile carriers may provide IPv6 on cellular while home Wi-Fi remains v4-only, compare both radios deliberately. This page does not reconfigure your router’s PD prefix, does not edit Windows firewall rules, and does not claim to be a compliance audit for IPv6-only federal mandates. Schools teaching networking labs prefer a no-install smoke check before students dig into ipconfig output. Streamers troubleshooting Discord voice oddities sometimes discover IPv6 path MTU issues, echo reachability is a first filter, not a full MTU lab. CDN engineers comparing client family support attach IPv6 Test screenshots beside synthetic probes from their side.

What this tool does

When you run the test, the page fetches IPv4 and dual-stack echo endpoints in parallel, displays the returned addresses, and flags whether the dual-stack response looks like IPv6. It does not guarantee end-to-end IPv6 to arbitrary websites, does not validate DNS64/NAT64 carrier setups in full, and does not rewrite Happy Eyeballs timers in the browser. Guidance explains that echo success means those specific hosts were reachable on the stacks that answered, not that every dependency in your app has AAAA records. Failures distinguish transport problems from endpoint downtime when possible, though public echoes can also be blocked by filters. Refresh after toggling VPN IPv6 settings to see changes. Notes remind you that third-party echo operators see the requests, same honesty as other IP tools. Pairing with DeviceHub /api/client-ip via the IP Address tool adds Cloudflare-observed context that may differ from ipify literals under split tunnels. The UI stays permission-free: permissions none, no device pickers. Results are session diagnostics you choose to copy. IPv4-only success with dual-stack fallback to v4 is a common home ISP outcome and should be read as incomplete IPv6 client path for that echo, not as DeviceHub inventing addresses. Temporary IPv6 outages after router firmware updates show up here quickly for smoke checks before blaming application code.

When to use it

Use IPv6 Test after ISP upgrades, when enabling router IPv6, when VPN apps advertise dual-stack, before blaming application code for AAAA failures, and when comparing cellular versus Wi-Fi family support. Prefer IP Address when you only need one public IPv4 string plus Cloudflare metadata. Prefer WebRTC Leak Test when ICE candidates reveal local or public families beyond HTTP echoes. Prefer HTTPS Reachability Check when a specific HTTPS hostname’s reachability from Cloudflare edge is the question, not your dual-stack client path. Prefer DNS Privacy Check when the privacy question is resolver identity rather than IP family. Use in classrooms before teaching traceroute6 so students confirm basic echo reachability. Use when a partner insists your network is IPv6-ready and you need a quick counterexample. Avoid treating a single api64 IPv6 success as proof every SaaS dependency is dual-stack. Avoid assuming Safari and Chrome will always prefer the same family under Happy Eyeballs, test the browser users actually run. Retest after disabling experimental IPv6 VPN toggles that half-break tunnels. Combine with Connection Information only as a soft hint; effectiveType never proves IPv6.

How it works

Public echo services answer with the client address they observe on the accepted connection. api.ipify.org is commonly used for IPv4 JSON echoes. api64.ipify.org is dual-stack oriented and may return IPv6 when your path supports it, or fall back to IPv4 otherwise, DeviceHub surfaces that behavior instead of pretending a failed v6 connect is a v6 address. IPv6 depends on host configuration, router advertisements or DHCPv6, ISP routing, and firewall allowances; any break in that chain yields v4-only echoes. Browser fetch uses the platform network stack; extensions and VPNs sit in the middle. Third-party echoes see your request, document that privacy cost the same way IP Address documents ipify fallbacks. DeviceHub may also expose Cloudflare client-ip on related tools, but this page’s primary signal is echo reachability across families. No Permissions API prompts appear. Secure context is standard sitewide HTTPS. Happy Eyeballs (RFC 8305 style behavior in clients) can race v6 and v4; timing differences across runs are expected on flaky links. DNS lookups for echo hostnames themselves may use whatever resolver your OS selected, another reason DNS Privacy Check sits nearby in the suite. This tool does not craft raw ICMPv6, does not read router ND tables, and does not replace isp-provided IPv6 self-tests when those exist, it complements them with a browser-visible smoke check.

Step-by-step instructions

1. Open IPv6 Test over HTTPS on the network and VPN state you care about, including the browser engine your users run.
2. Click Run and wait for both IPv4 and dual-stack echo requests to settle before screenshotting.
3. Note whether the dual-stack endpoint returned an IPv6 literal or an IPv4 fallback, and record both addresses.
4. If IPv6 is missing, check OS address assignment and router IPv6 status, then retest off VPN to isolate tunnel filtering.
5. Open IP Address for DeviceHub /api/client-ip context and compare families when edge metadata is available.
6. Document third-party echo privacy: ipify endpoints see these requests whenever the test runs.

Common problems

Users expect api64 to always return IPv6 and treat IPv4 answers as bugs, fallback is normal without a working v6 path. VPNs that only tunnel IPv4 break v6 while leaving local RA addresses visible in OS settings, confusing side-by-side comparisons. Corporate firewalls that allow AAAA DNS but drop v6 TCP yield timeouts that look like endpoint death. Mobile IPv6 on LTE with Wi-Fi v4-only produces different results when switching radios mid-ticket. Browser extensions blocking third-party fetches fail echoes entirely. Assuming DeviceHub can enable IPv6 on the ISP side wastes escalation time. Mixing results from different times of day on flaky tunnels creates false churn narratives, capture timestamps. NAT64 environments may make v4-only apps work while true v6 echoes still fail, read outcomes carefully. Some networks assign temporary privacy addresses that rotate; consecutive runs showing different v6 literals can still both be healthy.

Privacy explanation

Echo endpoints necessarily observe your connection and returned public addresses. DeviceHub does not hide that third-party cost. Permissions stay none, no mic, camera, or clipboard prompts. Closing the tab ends fetches; nothing continues polling families in the background. Treat returned IPv6 literals like other network identifiers when sharing screenshots. Prefer running tests only when you need the diagnostic so you minimize unnecessary third-party observations. Pair privacy-sensitive workflows with DNS Privacy Check and WebRTC Leak Test for a fuller picture of what your path reveals, remembering each tool has distinct honesty limits.