Every 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 addresses, which was introduced initially, has been distributed, hence the so-called IPv4 IP addresses are progressively being replaced with IPv6 addresses. Every domain name which opens an internet site 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 is made up of four groups of numbers from 1 to 255 divided with a dot, while with the IPv6 system it is called AAAA and it is comprised of eight sets of hexadecimal numbers i.e. this kind 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.