AAAA is a domain record, which is basically the IPv6 address of the web server in which the domain is hosted. The IPv6 system was intended to replace the present IPv4 system where each IP consists of four groups of decimal numbers ranging from 1 to 255 e.g. 126.96.36.199. On the other hand, an IPv6 address includes 8 groups of four hexadecimal digits - from 0 to 9 and from A to F. The cause of this transformation is the substantially smaller number of unique IPs that the current system supports and also the rapid increase of gadgets that are connected to the Internet. An example of an IPv6 address would be 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you wish to forward a domain name to a server which uses this kind of an address, you will have to set up an AAAA record for it, and not the widespread A record, which is an IPv4 address. Both records provide the exact same function, yet different notations are used, so as to separate the two types of addresses.