Each device which is connected to the world wide web has a special identifier referred to as IP (Internet Protocol) address. This includes PCs, web servers, smartphones, switches, etcetera. The pool of IP addresses, that was introduced initially, is already distributed, hence the so-called IPv4 IP addresses are slowly getting replaced with IPv6 addresses. Every domain which opens a website comes with an IP record, that is the address of the server where it's hosted. When using the IPv4 system, the record is called A and it is made up of four groups of numbers from 1 to 255 separated using a dot, while within the IPv6 system it is called AAAA and it is made up of eight sets of hexadecimal numbers i.e. this sort of records use digits from 0 to 9 and letters from A to F. An illustration of an AAAA record is 2010:0c48:43d3:2142:1012:8c3a:2475:2435 and this format works with a significantly greater number of IPs than the IPv4 format.