Every device that is connected to the web has a unique identifier referred to as IP (Internet Protocol) address. This includes computers, web servers, smartphones, switches, etcetera. The pool of IPs, which was introduced initially, is already distributed, hence the so-called IPv4 IP addresses are steadily being replaced with IPv6 addresses. Every domain which opens an internet site 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 comprised of 4 sets of numbers from 1 to 255 separated with a dot, while within the IPv6 system it's called AAAA and it is made up of eight groups of hexadecimal numbers i.e. this kind 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 significantly greater number of IPs than the IPv4 format.