AAAA is a domain record, which is essentially the IPv6 address of the server in which the domain is hosted. The IPv6 system was intended to replace the present IPv4 system where each IP is made up of 4 groups of decimal numbers which range from 1 to 255 e.g. 22.214.171.124. However, an IPv6 address features 8 sets of four hexadecimal numbers - from 0 to 9 and from A to F. The reason behind this modification is the tremendously smaller range of unique IPs the present system supports as well as the fast increase of products which are connected to the world wide web. A good example of an IPv6 address is 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you want to forward a domain to a machine that uses this kind of an address, you'll have to create an AAAA record for it, and not the widespread A record, which is an IPv4 address. The 2 records provide the exact same function, yet different notations are used, to identify the two sorts of addresses.