AAAA is a domain name record, which is basically the IPv6 address of the web server where the domain name is hosted. The IPv6 system was intended to replace the current IPv4 system in which each IP address is comprised of 4 sets of decimal numbers between 1 to 255 e.g. 5.168.208.143. However, an IPv6 address features 8 sets of four hexadecimal numbers - ranging from 0 to 9 and from A to F. The main reason for this transformation is the substantially smaller range of unique IPs that the current system supports and the fast increase of devices 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 want to forward a domain address to a machine that uses this kind of an address, you will have to set up an AAAA record for it, not the widespread A record, that is an IPv4 address. The 2 records provide the very same function, but different notations are used, so as to separate the two sorts of addresses.