AAAA is a domain name record, which is essentially the IPv6 address of the server in which the domain is hosted. The IPv6 system was introduced to replace the current IPv4 system in which each IP address is comprised of 4 groups of decimal digits which range from 1 to 255 e.g. 18.104.22.168. However, an IPv6 address includes 8 sets of four hexadecimal digits - ranging from 0 to 9 and from A to F. The main reason for this modification is the significantly smaller number of unique IPs the present system supports and also the rapid increase of products that 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 wish to forward a domain to a server which uses this kind of an address, you'll have to create an AAAA record for it, and not the commonly used A record, which is an IPv4 address. Both records have the same exact function, yet different notations are used, so as to separate the two sorts of addresses.