Free AAAA record lookup
AAAA Record Lookup
Free, no sign-up. We only fetch the public URL you enter.
Short answer
Enter a domain such as example.com above and the AAAA record lookup queries DNS for its AAAA records. You get every IPv6 address currently published for the name and the TTL in seconds. An empty result means the name is IPv4-only; an address that your host does not actually serve means IPv6 visitors may see errors even though IPv4 works fine. For ongoing reachability alerts on your homepage, monitordefend runs an uptime check every five minutes and emails you when it fails.
- Free, no sign-up: all AAAA (IPv6) records of a hostname with TTL.
- No AAAA record is valid – the site is then reached over IPv4 only.
- A stale AAAA record breaks the site for IPv6-first networks.
myshop.com. 3600 IN AAAA 2001:db8:4a1::10 myshop.com. 3600 IN AAAA 2001:db8:4a1::11 api.myshop.com. – no AAAA record (IPv4 only)
This free AAAA record lookup shows the IPv6 address behind any domain in seconds. A growing share of visitors – especially on mobile networks – connect over IPv6 first, so the quad-A record decides whether they reach your site directly, fall back to IPv4 after a delay or hit a timeout. The lookup tells you what DNS publishes for that path, along with the TTL that governs caching.
How does the AAAA record lookup work?
You type a hostname and run the check. The tool sends a DNS query of type AAAA for that exact name and lists each record it receives: the 128-bit IPv6 address in its usual compressed notation and the TTL. The query covers one name at a time, so check the root domain, www and any subdomain you serve separately.
IPv6 addresses look intimidating, but you only need to compare them with what your provider shows in its control panel. The compressed form drops leading zeros and replaces one run of zero blocks with a double colon, so 2001:0db8:04a1:0000:0000:0000:0000:0010 and 2001:db8:4a1::10 are the same address.
What is an AAAA record?
An AAAA record – pronounced “quad-A” – maps a domain or subdomain to an IPv6 address. The name comes from the address length: an IPv6 address is four times as long as the 32-bit IPv4 address an A record holds. Functionally it is the IPv6 twin of the A record, used when your website, API or other infrastructure is reachable over IPv6.
- AAAA
Client asks for IPv6 and IPv4 at the same time - IPv6
Tries 2001:db8:4a1::10 first - 250 ms
No answer – starts IPv4 in parallel - A
Connects to 203.0.113.10 and loads the page
Both record types usually live side by side on the same hostname. A dual-stack site publishes an A record for IPv4 and an AAAA record for IPv6, and every client chooses the protocol its network supports. Neither record replaces the other, and a domain with only A records is perfectly valid.
When should you check an AAAA record?
IPv6 issues have a distinctive fingerprint: the site works for you but not for a colleague, works on office Wi-Fi but not on a phone, or loads only after a noticeable pause. Whenever a problem depends on the network rather than the device, look at the AAAA record first.
- A site works on some networks but fails or stalls on others (IPv6 vs IPv4 path).
- You just enabled IPv6 on your hosting, CDN or load balancer.
- You are verifying DNS changes during a server or provider migration.
- Users of IPv6-capable mobile carriers report timeouts that you cannot reproduce.
- A certificate authority or webhook sender reaches the wrong server over IPv6.
AAAA record vs A vs CNAME
AAAA points a name to an IPv6 address, A points it to an IPv4 address, and a CNAME makes the name an alias of another hostname – common for app integrations and SaaS subdomains. If a name is a CNAME, it cannot carry its own AAAA record; the IPv6 address then comes from whatever name the alias points to, so a lookup reflects the target’s records.
This matters during migrations: if you replace a CNAME with direct records, remember to add both an A and an AAAA record if the new destination is dual-stack. Adding only the A record silently turns an IPv6-enabled name into an IPv4-only one, which is harmless; copying an old AAAA record that the new server does not answer on is not.
Why a wrong AAAA record breaks the site for some visitors
Modern operating systems and browsers prefer IPv6 when both record types exist. Most of them use an algorithm known as Happy Eyeballs: they start the IPv6 connection, and if it does not succeed within a short delay they race an IPv4 connection in parallel. A broken AAAA record therefore often shows up as a slow first load rather than an outright failure – which makes it easy to overlook.
Not every client is that forgiving. Command-line tools, older libraries, some API clients and networks that offer IPv6 only (with IPv4 translated through NAT64) may simply fail. The result is an outage that affects a slice of your audience and that your own browser never shows you. If you cannot fix the IPv6 path immediately, removing the AAAA record is a safe temporary measure.
Multiple AAAA records and redundancy
Like A records, AAAA records can be repeated. Several IPv6 addresses on one name are common for redundancy, for spreading load across servers or for geo-distributed setups behind anycast. Clients receive the whole set and pick an address, retrying another if the first fails – but DNS itself does not check health, so a dead address stays in rotation until you remove it.
Keep the IPv4 and IPv6 record sets consistent. If the A records point at three servers but the AAAA record still names a fourth machine that you retired months ago, IPv6 visitors end up somewhere different from everyone else.
Do you need an AAAA record?
Only if your host, CDN or load balancer actually serves your site over IPv6. Many managed platforms and CDNs enable it by default and publish the AAAA record for you; on a self-managed server you need an IPv6 address on the interface, a firewall that allows traffic on ports 80 and 443 over IPv6, and a web server that listens on it.
Before publishing the record, test the IPv6 path directly – for example with curl -6 https://example.com from a machine that has IPv6 connectivity. Only when that request returns the expected page should the AAAA record go live. After publishing, run the lookup to confirm DNS hands out the right address.
Common AAAA record mistakes
Most IPv6 trouble traces back to a handful of configuration slips. Running through them takes a minute and saves hours of guessing.
- An AAAA record copied from the old server survives a migration that only updated the A record.
- The server has an IPv6 address, but the firewall only opens ports 80 and 443 for IPv4.
- The web server listens on 0.0.0.0 (IPv4 only) instead of also binding to [::].
- A typo in a long address – one wrong hex digit sends visitors to an unused address.
- A link-local (fe80::) or documentation (2001:db8::) address published by mistake.
Propagation and caching of new AAAA records
A new or changed AAAA record is not visible everywhere at once. Resolvers keep cached answers for the TTL of the previous record, and some also cache the fact that no AAAA record existed, based on the negative-caching value in the zone’s SOA record. If a freshly added address does not appear yet, waiting out these timers is usually all it takes.
IPv6 and monitordefend
Use this lookup whenever you touch IPv6 settings. monitordefend does not monitor DNS records or test IPv4 and IPv6 paths separately; its uptime check loads your homepage every five minutes from Germany and emails you when the site stops answering.
Frequently asked questions
What is an AAAA record?
An AAAA (quad-A) record maps a domain or hostname to an IPv6 address. It is the IPv6 equivalent of the A record, which holds an IPv4 address.
How do I check the AAAA record for my domain?
Enter your domain above and run the check. The tool returns every IPv6 address currently published as an AAAA record for that name, together with its TTL.
Do I need an AAAA record if I already have an A record?
Not necessarily. An A record alone is enough if your site is not reachable over IPv6. Add an AAAA record once your host, CDN or load balancer supports IPv6 and you have tested that path.
Why can an incorrect AAAA record break the site for some visitors?
Clients that prefer IPv6 try the AAAA address first. If it is unreachable, they may wait for a fallback or fail outright, while visitors on IPv4 see no problem at all.
Can I have multiple AAAA records?
Yes. Several IPv6 addresses on one name are common for redundancy, load distribution and geo-distribution. Remove addresses of servers that are no longer in service.
If I publish both A and AAAA, which one gets used?
Most modern clients request both and connect over whichever works best, usually trying IPv6 first and falling back to IPv4 quickly if that attempt stalls.
Why don’t I see my new AAAA record immediately?
DNS answers are cached according to their TTL, and resolvers may also cache the earlier “no record” answer. Until those caches expire, some resolvers return the old state.
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