What does IPv6 readiness mean?

A domain is IPv6-ready when it has AAAA records alongside its A records and the servers those records point to actually answer over IPv6 — publishing the record alone isn't enough.

Is adding an AAAA record risky if my IPv6 setup isn't fully tested?

Yes — a broken or half-working IPv6 path can be worse than having none, since some clients wait out a connection timeout on IPv6 before falling back to IPv4. Confirm the whole path works before publishing the record.

Do I need IPv6 if all my traffic still looks fine over IPv4?

IPv4 address exhaustion means an increasing share of mobile and ISP networks run IPv6-only internally, translating back to IPv4 for domains that lack it — traffic can look fine today while depending entirely on that translation layer working.

IPv6 Readiness: What It Means for a Domain

IPv4 addresses ran out years ago at the allocation level. IPv6 readiness is no longer a forward-looking nicety — it's whether a domain still depends entirely on translation layers that mobile carriers and ISPs increasingly treat as a legacy compatibility path.

What IPv6 Readiness Means

A domain is IPv6-ready when it has AAAA records alongside its A records, and the servers those AAAA records point to actually answer over IPv6 — not just that the DNS record exists.

Why It Matters Now

The five Regional Internet Registries have no more fresh IPv4 space left to allocate. Many mobile carriers already run IPv6-only internally, translating back to IPv4 on the fly (NAT64/CLAT) only for domains that still need it. A domain with no IPv6 path is entirely dependent on that translation layer working correctly for an increasing share of its visitors.

What a Readiness Check Actually Verifies

AAAA records exist for the apex domain and its common subdomains (www, etc.)
The IPv6 address actually answers, not just that the record is published
Mail servers named in MX records also have AAAA records — a frequently missed gap, since mail delivery can silently stay IPv4-only
The domain's own nameservers are reachable over IPv6, which is easy to overlook entirely

What "Dual-Stack" Means

Dual-stack simply means both A and AAAA records are published. Modern clients use the Happy Eyeballs algorithm: they try IPv6 and IPv4 in parallel and use whichever connects first, falling back automatically if IPv6 fails. This makes adding AAAA records low-risk — for a properly working setup.

The Pitfall: Half-Working Is Worse Than Absent

A broken or misconfigured IPv6 path can be worse than having none at all: some clients still wait out a connection timeout on IPv6 before falling back to IPv4, adding real delay instead of avoiding it. Publishing an AAAA record without first confirming the entire IPv6 path actually works end to end is the most common mistake.

Check a Domain's IPv6 Readiness

Run an IPv6 readiness check →Next: Does DNS resolver speed matter? →

Try it on your domain

See the theory in practice — run a IPv6 Readiness Check for your own domain.