AAAA Record Lookup
Find the IPv6 address associated with any domain.
Perform AAAA Lookup
What is a AAAA record?
An AAAA record (pronounced "quad-A") maps a hostname to an IPv6 address. AAAA is the IPv6 counterpart of the A record — the "4A" name refers to the fact that IPv6 addresses are 128 bits (four times the 32 bits of IPv4). While IPv4 is running out of available addresses, IPv6 provides a practically inexhaustible pool: 340 undecillion unique addresses.
A host can have both A and AAAA records at the same hostname, in which case dual-stack clients choose between them using the "Happy Eyeballs" algorithm (RFC 8305), which races connection attempts on both protocols and uses whichever responds first. In practice, most modern operating systems prefer IPv6 where available because of its larger path MTU and fewer NAT traversals.
IPv6 addresses are 32 hexadecimal digits grouped in blocks of four separated by colons — for example, 2001:4860:4860::8888 (Google Public DNS). Leading zeros within a block can be omitted, and a single run of all-zero blocks can be compressed to ::, but only once per address.
Adoption varies widely. Residential ISPs in North America, Europe, and parts of Asia now deliver IPv6 to most customers, and major CDNs (Cloudflare, Akamai, Fastly) publish AAAA records by default. Enterprise networks and many cloud providers still lag behind — plenty of production hosts only advertise A records for historical or operational reasons.
How to read the results
The result panel shows each IPv6 address returned, along with its TTL. A single AAAA answer is the common case; multiple AAAAs indicate load balancing, identical to how multiple A records work.
To see whether your network can actually reach the address, try curl -6 https://example.com (forces IPv6) or ping6 example.com. If the hostname has an AAAA record but your network has no IPv6 path out, connections will fall back to IPv4 — this is normally transparent, but on broken networks it can cause long timeouts before the fallback triggers.
Many dual-stack hostnames publish shorter TTLs on AAAA than A because IPv6 deployments are still evolving. A 300-second TTL on AAAA alongside a 3600-second TTL on A at the same hostname is not unusual.
Common issues
- No AAAA records returned. The host is IPv4-only. Many older deployments, enterprise networks, and legacy hosting providers still don't publish IPv6 addresses. Check the A record lookup — almost every hostname has at least one of the two.
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Host reachable on IPv4 but AAAA fails to connect. Common causes: IPv6 firewall rules differ from IPv4 (a frequent oversight), the server isn't bound to the IPv6 interface, or an upstream ISP has IPv6 connectivity issues. Test with
curl -4andcurl -6to isolate the protocol. - Slow initial page load on IPv6-capable clients. The Happy Eyeballs algorithm races both stacks, but a misconfigured AAAA that silently drops packets causes the client to wait ~250ms before falling back to IPv4. If an AAAA exists, it must actually work — a broken AAAA is worse than no AAAA.
- AAAA record with unexpected /64 host portion. The lower 64 bits of an IPv6 address are often derived from the server's MAC address (SLAAC) or a privacy extension. If the host portion changes unpredictably, the server may be using dynamic addressing — fine for clients, bad for authoritative services. Use a static address for any public endpoint.
- AAAA published but no IPv6 connectivity at your ISP. Your ISP hasn't rolled out IPv6 to your subnet. The AAAA is correctly published globally; you just can't reach it from where you are. Use a VPN with IPv6 support or a public IPv6 tunnel (Hurricane Electric) to test end-to-end.
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