Each device that's connected to the web has a special identifier called IP (Internet Protocol) address. This includes personal computers, web servers, smartphones, switches, etc. The pool of IPs, which was introduced initially, is already distributed, therefore the so-called IPv4 IP addresses are gradually getting replaced with IPv6 addresses. Every domain which opens a site has an IP record, that is the address of the server where it is hosted. Using the IPv4 system, the record is called A and it consists of four sets of numbers from 1 to 255 divided with a dot, while within the IPv6 system it is called AAAA and it is comprised of eight groups of hexadecimal numbers i.e. this kind of records use numbers from 0 to 9 and letters from A to F. An example of an AAAA record is 2010:0c48:43d3:2142:1012:8c3a:2475:2435 and this format supports a considerably larger amount of IPs in comparison with the IPv4 format.