Each device which is connected to the world wide web has a distinctive identifier known as IP (Internet Protocol) address. This includes computer systems, web servers, smartphones, switches, etcetera. The pool of addresses, which 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 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 comprises of four sets of numbers from 1 to 255 separated using a dot, while within the IPv6 system it is called AAAA and it is made up of eight groups of hexadecimal numbers i.e. this sort of records use digits 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 substantially bigger number of IPs compared with the IPv4 format.