Each device that is connected to the web has a unique identifier named IP (Internet Protocol) address. This includes computer systems, web servers, smartphones, switches, and so on. The pool of IP addresses, that was introduced at first, has already been distributed, so the so-called IPv4 IP addresses are gradually being replaced with IPv6 addresses. Every domain name that opens a website has 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 consists of four groups of numbers from 1 to 255 divided using a dot, while in the IPv6 system it's called AAAA and it is made up of 8 groups of hexadecimal numbers i.e. this sort of records use numbers 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 is designed for a substantially bigger amount of IPs when compared with the IPv4 format.