AAAA is a domain record, that is in essence 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 IP comprises of 4 groups of decimal numbers which range from 1 to 255 e.g. 18.104.22.168. In contrast, an IPv6 address includes eight sets of 4 hexadecimal numbers - which range from 0 to 9 and from A to F. The cause of this transformation is the significantly smaller number of unique IPs which the current system supports and also the rapid increase of products that are connected to the Internet. A good example of an IPv6 address is 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you wish to direct a domain address to a machine which uses this kind of an address, you need to set up an AAAA record for it, and not the commonly used A record, which is an IPv4 address. Both records provide the same exact function, yet different notations are used, to distinguish the two types of addresses.