Every device that's connected to the web has a specific identifier referred to as IP (Internet Protocol) address. This includes personal computers, web servers, smart phones, switches, and so on. The pool of IP addresses, which was introduced originally, has been distributed, hence the so-called IPv4 IP addresses are progressively being replaced with IPv6 addresses. Every domain name that opens a website comes with an IP record, that is the address of the server where it's hosted. Using the IPv4 system, the record is called A and it is made up of four groups of numbers from 1 to 255 separated with a dot, while with the IPv6 system it is called AAAA and it comprises of eight groups of hexadecimal numbers i.e. this type 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 supports a substantially bigger number of IPs compared with the IPv4 format.