AAAA is a domain record, that is essentially the IPv6 address of the web server in which the domain is hosted. The IPv6 system was intended to replace the current IPv4 system in which every IP address is comprised of four groups of decimal digits between 1 to 255 e.g. 18.104.22.168. In contrast, an IPv6 address features 8 groups of 4 hexadecimal digits - which range from 0 to 9 and from A to F. The main reason for this modification is the tremendously smaller number of unique IPs which the existing system supports as well as the rapid increase of gadgets that are connected to the world wide web. An 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 that uses this kind of an address, you will have to create an AAAA record for it, not the widespread A record, that is an IPv4 address. Both records provide the exact same function, but different notations are used, so as to separate the two forms of addresses.