DNS lookup

Check the AAAA record and IPv6 address of a domain online

An AAAA record is the IPv6 twin of the A record. Clients on networks with IPv6 use it to learn which address to connect to.

What the AAAA record shows

Many hosts publish both A and AAAA records. A browser on an IPv6 network tries the IPv6 address first and falls back to IPv4 when it does not answer.

A broken AAAA record makes a site slow or unreachable for part of the visitors, while IPv4 users see no problem. Addresses look like 2606:4700::6810:84e5, where a double colon replaces a run of zeros.

When you need it

Check that a site answers over IPv6 after you enable it at the host
Find out why a site opens for some users and hangs for others
Check whether a target site of your scraper also has an IPv4 address

Questions about DNS records

01Do I need an AAAA record?

Only if your server listens on IPv6. Publishing an AAAA record for a server without IPv6 breaks the site for visitors whose networks prefer IPv6.

02Will IPv4 proxies open a site that has AAAA records?

Yes, as long as the site also has an A record. A site with only AAAA records cannot be reached through IPv4 proxies.

03Why does a domain have AAAA records but IPv6 does not work?

The server may not listen on that address or a firewall may block it. Ask the host to check the IPv6 setup or remove the record.

04How do I read an IPv6 address in an AAAA record?

It is eight groups of four hex digits separated by colons. Leading zeros in a group are dropped, and one run of zero groups becomes ::, so 2001:db8::1 and 2001:0db8:0:0:0:0:0:1 are the same address.

05Does an IPv6 mail server need a PTR record?

Yes. Gmail requires PTR from every sender, and mail over IPv6 must also pass SPF or DKIM. The owner of the subnet, usually the host, sets the reverse record.