What is an AAAA record (IPv6)?

An AAAA record (quad-A record) maps a domain name to an IPv6 address:

tidalmail.com AAAA 2001:db8::1

IPv6 addresses are 128-bit (versus IPv4's 32-bit), written as eight groups of hexadecimal digits.

Email implications:

Some networks are IPv6-only. Without AAAA records, they cannot reach your server.

IPv6 reputation is separate from IPv4. New IPv6 addresses may need warming.

SPF records should include IPv6 if you send over it.

Many servers support both. Having both A and AAAA records ensures maximum connectivity.

A second coordinate system for modern ships. Some routes only work with the new navigation system.