AAAA is a domain address record, that is basically the IPv6 address of the web server in which the domain name is hosted. The IPv6 system was intended to replace the present IPv4 system in which each Internet protocol address is made up of 4 groups of decimal digits between 1 to 255 e.g. 5.168.208.143. However, an IPv6 address has eight sets of 4 hexadecimal digits - which range from 0 to 9 and from A to F. The reason for this transformation is the tremendously smaller range of unique IPs that the existing system supports and the quick increase of products which are connected to the Internet. An example of an IPv6 address would be 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you'd like to forward a domain name to a server which uses this kind of an address, you have to set up an AAAA record for it, not the widely used A record, which is an IPv4 address. The 2 records have the exact same function, yet different notations are used, to differentiate the two types of addresses.