Every single device that's connected to the world wide web has a specific identifier known as IP (Internet Protocol) address. This includes computer systems, web servers, smart phones, switches, etc. The pool of addresses, which was introduced initially, is already distributed, so the so-called IPv4 IP addresses are gradually being replaced with IPv6 addresses. Every domain name which opens a site 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 is made up of four groups of numbers from 1 to 255 divided using a dot, while with the IPv6 system it's called AAAA and it comprises of 8 groups of hexadecimal numbers i.e. this sort of records use numbers from 0 to 9 and letters from A to F. A good example of an AAAA record is 2010:0c48:43d3:2142:1012:8c3a:2475:2435 and this format supports a considerably bigger amount of IPs when compared with the IPv4 format.