Every single device which is connected to the web has a special identifier known as IP (Internet Protocol) address. This includes personal computers, web servers, smart phones, switches, etcetera. The pool of IP addresses, that was introduced initially, is already distributed, so the so-called IPv4 IP addresses are gradually getting replaced with IPv6 addresses. Every domain that opens a site comes with an IP record, that is the address of the server where it is hosted. When using the IPv4 system, the record is called A and it is made up of four sets of numbers from 1 to 255 separated by a dot, while in the IPv6 system it's called AAAA and it consists of eight groups of hexadecimal numbers i.e. this type 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 supports a significantly bigger number of IPs than the IPv4 format.