AAAA is a domain name record, that's in essence the IPv6 address of the server where the domain is hosted. The IPv6 system was designed to replace the existing IPv4 system where each IP consists of 4 groups of decimal digits between 1 to 255 e.g. 188.8.131.52. On the other hand, an IPv6 address has eight groups of 4 hexadecimal numbers - from 0 to 9 and from A to F. The main reason for this change is the considerably smaller number of unique IPs which the present system supports and also the fast increase of units 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 forward a domain to a server that uses such an address, you will have to set up an AAAA record for it, not the widely used A record, which is an IPv4 address. The 2 records deliver the exact same function, yet different notations are used, so as to identify the two sorts of addresses.