How to Check a Domain's IPv6 Address (AAAA Record)

To check whether a domain publishes IPv6, query its AAAA record. An AAAA answer contains an IPv6 address, while an A answer contains IPv4. Seeing an AAAA record is evidence that the name advertises an IPv6 endpoint in the DNS view you queried; it does not prove that the endpoint is reachable from every network or that the website works correctly over IPv6. DNS publication, routing, firewall rules, TLS, and application configuration all need to align. Conversely, no AAAA answer means that the queried name did not return IPv6 data at that time, not that the entire domain or organization has no IPv6 deployment.

Query the right name and record type

Check the hostname users actually visit, including whether it begins with www or uses an application subdomain. A root domain can publish IPv6 while www does not, or the reverse. Query AAAA specifically and compare with A to understand whether the name is IPv4-only, IPv6-only, or dual-stack. If a CNAME is returned, follow the target chain; the alias itself may not show the address. Repeat the lookup from an appropriate resolver if the record was just added, and note the time and TTL so you can distinguish an old cached result from a configuration that never reached the authoritative zone.

An IPv6 address is written in hexadecimal groups separated by colons, and consecutive zero groups can be compressed with a double colon. This notation can look unfamiliar next to dotted IPv4. Do not try to compare IPv6 addresses as if they were IPv4 or infer that an address is private simply because it looks different. If you administer the endpoint, verify that the address is assigned to the intended interface, routed from the internet, and permitted by host and cloud firewalls. Publishing AAAA before the endpoint is reachable can cause a portion of clients to encounter failures, depending on their connection-selection behavior.

Test service reachability separately

After confirming the AAAA record, test the application over IPv6 from a network that actually has IPv6 connectivity. Confirm that the web server listens on the IPv6 interface and presents the correct certificate for the hostname. Check load balancers, CDN settings, security groups, and local firewalls; IPv4 and IPv6 often have separate rules, so allowing one family does not automatically allow the other. Also test dependent services such as APIs and image hosts if the page loads resources from multiple domains. A DNS lookup provides the destination address but cannot test any of these transport or application conditions.

• Inspect AAAA for every important hostname, not only the apex.
• Follow CNAME targets until you find the published address.
• Verify firewall and routing policies for IPv6 independently of IPv4.
• Test HTTPS over IPv6 before announcing the AAAA record broadly.
• Monitor both address families after infrastructure or CDN changes.

A safe dual-stack rollout

A measured rollout begins by confirming that the provider supports IPv6 at every relevant layer: DNS, load balancing, firewalling, and origin connectivity. Test a staging hostname first, then validate from more than one IPv6-capable network. Monitor application logs for family-specific errors and compare success rates rather than relying on a single test. Keep rollback steps ready so you can remove or correct an AAAA record if it points at an endpoint that is not ready. If the environment uses a CDN, follow that provider's instructions and understand whether public DNS exposes edge addresses rather than your origin.

For the relationship between address families, see A and AAAA records compared and the broader IPv4 and IPv6 guide. To check the public answer, use the domain lookup tool and read IPv4 and IPv6 results independently. The important distinction is simple: a published AAAA record is a DNS fact; end-to-end IPv6 support is a service property that must be tested across the whole connection path.

Watch for partial IPv6 deployment

IPv6 readiness is often uneven across a service. The public website may have an AAAA record while an API, authentication callback, image host, or payment endpoint remains IPv4-only. That can create a page that begins loading but fails on one dependency for IPv6-capable users. Inventory all hostnames used by the application and check the intended address family for each. If a CDN fronts several origins, clarify whether IPv6 ends at the edge or continues to the backend. Log connection failures by address family so you can distinguish an IPv6 route problem from a general outage. A staged rollout and a tested rollback record are preferable to publishing AAAA broadly and waiting for customers to report the first broken request.