AAAA is a domain name record, that is essentially the IPv6 address of the web server in which the domain is hosted. The IPv6 system was intended to replace the current IPv4 system where every single IP address is made up of four sets of decimal numbers ranging from 1 to 255 e.g. 188.8.131.52. In contrast, an IPv6 address has eight sets of 4 hexadecimal digits - which range from 0 to 9 and from A to F. The reason for this change is the significantly smaller range of unique IPs the existing system supports as well as the rapid increase of units that are connected to the Internet. An example of an IPv6 address would be 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you want to forward a domain address to a web server which uses such an address, you'll have to set up an AAAA record for it, not the widespread A record, that is an IPv4 address. Both records provide the same exact function, but different notations are used, to identify the two types of addresses.