AAAA is a domain name record, that's essentially the IPv6 address of the web server in which the domain name is hosted. The IPv6 system was designed to replace the current IPv4 system in which every IP consists of 4 groups of decimal numbers between 1 to 255 e.g. 188.8.131.52. On the other hand, an IPv6 address has eight sets of four hexadecimal digits - from 0 to 9 and from A to F. The cause of this modification is the considerably smaller number of unique IPs which the existing system supports as well as the fast increase of gadgets that are connected to the world wide web. An 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 web server that uses such an address, you have to create an AAAA record for it, and not the commonly used A record, that is an IPv4 address. Both records provide the exact same function, yet different notations are used, in order to differentiate the two forms of addresses.