Each device that's connected to the web has a unique identifier called IP (Internet Protocol) address. This includes personal computers, web servers, smartphones, switches, etc. The pool of addresses, that was introduced at first, has already been distributed, so the so-called IPv4 IP addresses are steadily being replaced with IPv6 addresses. Every domain name that opens a website comes with an IP record, that is the address of the server where it is hosted. When using the IPv4 system, the record is called A and it consists of four groups of numbers from 1 to 255 separated by a dot, while with the IPv6 system it's called AAAA and it comprises of eight groups of hexadecimal numbers i.e. this kind of records use digits from 0 to 9 and letters from A to F. A good example of an AAAA record is 2010:0c48:43d3:2142:1012:8c3a:2475:2435 and this format is designed for a substantially greater amount of IPs in comparison with the IPv4 format.