Each device that's connected to the web has a unique identifier known as IP (Internet Protocol) address. This includes computers, web servers, smart phones, switches, and so on. The pool of addresses, that was introduced initially, has been distributed, hence the so-called IPv4 IP addresses are gradually being replaced with IPv6 addresses. Every domain that opens a website has an IP record, which is the address of the server where it is hosted. With the IPv4 system, the record is called A and it is comprised of four groups of numbers from 1 to 255 split up using a dot, while in the IPv6 system it is called AAAA and it comprises of eight groups of hexadecimal numbers i.e. this type of records use digits from 0 to 9 and letters from A to F. An example of an AAAA record is 2010:0c48:43d3:2142:1012:8c3a:2475:2435 and this format is designed for a significantly greater number of IPs in comparison with the IPv4 format.