Each device that's connected to the world wide web has a special identifier known as IP (Internet Protocol) address. This includes personal computers, web servers, smart phones, switches, and so on. The pool of IP addresses, that was introduced initially, is already distributed, so the so-called IPv4 IP addresses are progressively being replaced with IPv6 addresses. Every domain name which opens a site has an IP record, which is the address of the server where it's hosted. With the IPv4 system, the record is called A and it consists of four groups of numbers from 1 to 255 separated by a dot, while within the IPv6 system it's called AAAA and it comprises of 8 groups of hexadecimal numbers i.e. this kind 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 supports a significantly greater amount of IPs than the IPv4 format.