AAAA is a domain address record, that's in essence the IPv6 address of the web server where the domain is hosted. The IPv6 system was designed to replace the present IPv4 system in which each IP consists of four sets of decimal numbers ranging from 1 to 255 e.g. 18.104.22.168. In contrast, an IPv6 address includes eight groups of four hexadecimal digits - ranging from 0 to 9 and from A to F. The reason for this modification is the tremendously smaller selection of unique IPs which the existing system supports and also the speedy increase of devices 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 web server that uses this kind of an address, you will need to set up an AAAA record for it, not the widely used A record, which is an IPv4 address. Both records deliver the exact same function, yet different notations are used, so as to differentiate the two types of addresses.