Do I Have IPv6? Is It Working?

You have working IPv6 when your device holds a global IPv6 address and can reach IPv6-only or dual-stack destinations on the public internet — not merely when a settings screen shows "IPv6: On." In 2026 most large ISPs issue dual-stack service, but broken prefix delegation, firewall defaults and happy-eyeballs timeouts still leave millions of users on effective IPv4-only paths. The fastest check is a dedicated IPv6 test at speedtest.doctor, paired with public IP lookup and optional ping to confirm routing end to end.

IPv4 vs IPv6 in one minute

IPv4 uses 32-bit addresses — exhausted years ago, now extended by NAT and carrier-grade NAT (CGNAT). IPv6 uses 128-bit addresses, restoring end-to-end addressing so every device can have a globally unique address without port translation. Your home router typically receives a delegated prefix from the ISP and assigns addresses to phones, laptops and IoT gear via SLAAC or DHCPv6.

Dual-stack means both protocols run in parallel. That is ideal: legacy gear keeps IPv4 while modern traffic uses IPv6. Problems appear when IPv6 is half configured — the OS thinks it has IPv6, DNS returns AAAA records, but packets black-hole. Users blame "Wi-Fi" or "DNS" when the real fault is unrouted IPv6.

Symptoms of broken or missing IPv6

• First visit to a site is slow, refresh is fast — classic happy-eyeballs delay while IPv6 times out.
• Some apps connect, others hang — app uses IPv6-only APIs while browser fell back to IPv4.
• Gaming NAT type strict on IPv6-enabled titles — missing or filtered ICMPv6 neighbor discovery.
• Self-hosted services unreachable from outside — you may only have CGNAT IPv4 without proper IPv6 forwarding.

Step 1: Run the IPv6 test

Open /ip/ipv6 on speedtest.doctor. The test attempts connections over IPv6 to our measurement infrastructure at api.speedtest.doctor, reports whether a global IPv6 address is visible, and flags common failure modes (no address, link-local only, reachability failure). Run it on the network you care about — home Wi-Fi, office VLAN or phone on cellular — because IPv6 status differs per interface.

Repeat on ethernet if Wi-Fi fails. If ethernet passes and Wi-Fi fails, the router's wireless bridge or guest network may block IPv6 multicast. If both fail, suspect ISP prefix delegation or modem configuration.

Step 2: Confirm your public addresses

Visit What Is My IP to see IPv4 and IPv6 as servers on the internet observe them. Compare with the IPv6 test page. Mismatches between tools can indicate VPN split tunneling or proxy settings. For business troubleshooting, log the ASN — it identifies which network owns the prefix and helps support tickets.

Step 3: DNS and AAAA records

IPv6 depends on DNS returning AAAA records alongside A records. Use DNS lookup on a hostname you rely on (your bank, your employer VPN portal). If AAAA exists but connections fail, routing or firewall — not DNS — is the culprit. If AAAA is missing, the site may be IPv4-only; that is their choice, not your fault.

Slow DNS amplifies IPv6 pain. Pair lookup checks with a DNS speed test so you separate resolver latency from address-family issues.

Step 4: Ping and traceroute over IPv6

When reachability is ambiguous, ping a host that advertises IPv6 (many CDNs and ipv6.google.com respond). Follow with traceroute to see where hops stop. A trace that dies after your router points to LAN or CPE misconfiguration; a trace that dies at the ISP's first hop is a provider ticket.

Router and ISP checklist

1. 01Enable IPv6 on WAN — DHCPv6-PD or static delegation per ISP instructions.
2. 02Enable IPv6 on LAN — router advertises prefixes to clients (RA / DHCPv6).
3. 03Disable "IPv6 firewall = strict" profiles that block incoming ICMPv6 unless you understand the tradeoff.
4. 04Update modem firmware — older DOCSIS gateways drop delegated prefixes after power loss.
5. 05Retest with IPv6 test after each change.

IPv6 on mobile and VPN

Cellular networks often provide native IPv6; Wi-Fi calling may not. VPN clients vary: some tunnel IPv6 inside the VPN, some disable it, some leak IPv6 outside the tunnel. After connecting a VPN, rerun IPv6 test and VPN test. Privacy-conscious users should know IPv6 can bypass IPv4-only VPN assumptions.

When you do not need IPv6

If your ISP truly offers IPv4-only service and all your targets resolve without AAAA, you can operate — but you are increasingly rare. More often, disabling broken IPv6 on the client is a temporary workaround until ISP fixes prefix delegation. Document the workaround; do not treat it as a permanent solution.

Throughput and IPv6

IPv6 path MTU and hardware offload bugs occasionally cap throughput below IPv4 on the same line. Run the speed test on dual-stack, note which address family the session used, and compare with Connection Doctor for loss and bufferbloat on both paths. Symmetric performance is the goal; large gaps warrant router firmware updates or ISP escalation.

Privacy extensions and temporary addresses

Modern operating systems rotate privacy extensions (temporary IPv6 addresses) to reduce tracking. That is good for privacy but can confuse tests if you compare addresses across days. For troubleshooting, note whether the address shown at /ip is stable across reboots — unstable global prefixes often mean your ISP is delegating too short a prefix or your router is not storing delegation properly after power loss.

Enterprise networks may disable privacy extensions via policy. Home users should leave defaults unless a specific game or peer-to-peer app documents otherwise. After changing privacy settings, always rerun the IPv6 test because some stacks need a full interface bounce.

IPv6-only future and NAT64

Some mobile carriers already run IPv6-only core networks with NAT64/DNS64 to reach legacy IPv4 servers. Your phone may show IPv6-only connectivity while desktop on the same carrier Wi-Fi hotspot still uses IPv4. Testing each device independently prevents false conclusions. If NAT64 is misconfigured, only certain IPv4 destinations fail — a pattern that looks like "random site outages" rather than total offline status.

Documenting IPv6 issues for ISP support

When opening a ticket, attach: timestamped output from IPv6 test, your delegated prefix length if visible in router status, modem model, and whether wired ethernet fails the same as Wi-Fi. ISPs that do not yet offer IPv6 may ask you to disable it on the WAN — that is a valid workaround, but request a timeline for native dual-stack if you are on a long contract.

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