Each device that's connected to the web has a specific identifier known as IP (Internet Protocol) address. This includes personal computers, web servers, smart phones, switches, etc. The pool of IPs, that was introduced initially, is already distributed, hence the so-called IPv4 IP addresses are gradually being replaced with IPv6 addresses. Every domain name that opens a website comes with 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 is made up of four sets of numbers from 1 to 255 divided using a dot, while within the IPv6 system it's called AAAA and it consists of 8 groups of hexadecimal numbers i.e. this sort of records use numbers 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 works with a considerably bigger number of IPs when compared with the IPv4 format.