AAAA is a domain address record, that is basically the IPv6 address of the web server in which the domain is hosted. The IPv6 system was introduced to replace the existing IPv4 system where every single Internet protocol address is comprised of four groups of decimal numbers between 1 to 255 e.g. 126.96.36.199. In comparison, an IPv6 address includes eight sets of four hexadecimal digits - ranging from 0 to 9 and from A to F. The cause of this change is the considerably smaller range of unique IPs the current system supports and also the fast increase of products which are connected to the Internet. An illustration of an IPv6 address would be 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you want to forward a domain address to a server which uses this type of an address, you will need to set up an AAAA record for it, and not the widely used A record, which is an IPv4 address. The two records provide the same exact function, yet different notations are used, to separate the two types of addresses.