Every device which is connected to the world wide web has a specific identifier called IP (Internet Protocol) address. This includes computer systems, web servers, smart phones, switches, and so on. The pool of addresses, that was introduced at first, is already distributed, therefore the so-called IPv4 IP addresses are progressively being replaced with IPv6 addresses. Every domain that opens a website has an IP record, that is the address of the server where it is hosted. Using the IPv4 system, the record is called A and it is made up of four groups of numbers from 1 to 255 split up with a dot, while with the IPv6 system it's called AAAA and it consists of eight groups of hexadecimal numbers i.e. this sort of records use numbers 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 works with a substantially greater amount of IPs than the IPv4 format.