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AAAA record

The AAAA ("quad-A") record is the IPv6 counterpart of the A record: it maps a name to one 128-bit IPv6 address.

type code 28 RFC 3596

Live AAAA records from real domains

Checked at via public DNS
google.comAAAA
google.com. 133 IN AAAA 2a00:1450:4010:c0d::64
google.com. 133 IN AAAA 2a00:1450:4010:c0d::65
google.com. 133 IN AAAA 2a00:1450:4010:c0d::71
google.com. 133 IN AAAA 2a00:1450:4010:c0d::8b
cloudflare.comAAAA
cloudflare.com. 233 IN AAAA 2606:4700::6810:84e5
cloudflare.com. 233 IN AAAA 2606:4700::6810:85e5
wikipedia.orgAAAA
wikipedia.org. 15 IN AAAA 2a02:ec80:300:ed1a::1
facebook.comAAAA
facebook.com. 60 IN AAAA 2a03:2880:f113:81:face:b00c:0:25de
DNS Query: AAAA records for google.com →

What the AAAA record does

The name comes from the address size: four times the 32 bits of an A record. A name that has both A and AAAA records is dual-stack. Clients that have IPv6 connectivity generally prefer it and fall back to IPv4 using Happy Eyeballs (RFC 8305), so a broken AAAA record shows up as slow page loads rather than outright failure.

Like A, AAAA may be used at the zone apex and alongside other record types at the same name.

Zone-file syntax

www.example.com.  3600  IN  AAAA  2001:db8::10

Wire format: RDATA is 16 octets in network byte order. Zone files may use any valid IPv6 text form; :: compression is fine.

Fields

FieldMeaning
OwnerThe name being resolved.
TTLCache lifetime in seconds. Keep it in step with the A record so both families change together.
AddressIPv6 address in RFC 4291 text form, without brackets or a prefix length.

Common mistakes

  • Publishing AAAA for a host whose web server is not listening on IPv6, or whose firewall blocks it. IPv6 users get timeouts first.
  • Using a link-local (fe80::) or unique-local (fd00::/8) address copied from ip addr.
  • Forgetting AAAA on the mail host while publishing it for the web, or the reverse, and assuming both are covered.

Specification

  • RFC 3596: DNS Extensions to Support IP Version 6

Related record types

  • A: map a hostname to an IPv4 address
  • PTR: reverse DNS from an IP address to a name
  • HTTPS: ALPN, address hints and ECH for websites

All DNS record types