AAAA is a domain record, that is essentially the IPv6 address of the web server in which the domain is hosted. The IPv6 system was introduced to replace the current IPv4 system where every single Internet protocol address is made up of four sets of decimal digits between 1 to 255 e.g. 184.108.40.206. However, an IPv6 address features eight sets of four hexadecimal digits - which range from 0 to 9 and from A to F. The reason behind this transformation is the considerably smaller selection of unique IPs that the current system supports and also the fast increase of gadgets which are connected to the Internet. An illustration of an IPv6 address is 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you need to forward a domain address to a machine that uses this type of an address, you will have to set up an AAAA record for it, not the commonly used A record, which is an IPv4 address. Both records have the same exact function, but different notations are used, to identify the two types of addresses.