AAAA is a domain record, that's essentially the IPv6 address of the server where the domain name is hosted. The IPv6 system was introduced to replace the present IPv4 system where each and every Internet protocol address is made up of four groups of decimal numbers between 1 to 255 e.g. 5.168.208.143. In contrast, an IPv6 address has eight groups of 4 hexadecimal digits - ranging from 0 to 9 and from A to F. The reason behind this modification is the significantly smaller number of unique IPs that the existing system supports and the quick increase of devices that are connected to the Internet. A good example of an IPv6 address would be 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you need to forward a domain address to a machine which uses this sort of an address, you need to create an AAAA record for it, and not the widespread A record, which is an IPv4 address. Both records deliver the exact same function, but different notations are used, to distinguish the two types of addresses.