Each device that is connected to the Internet has a unique identifier referred to as IP (Internet Protocol) address. This includes computers, web servers, smart phones, switches, etc. The pool of IP addresses, that was introduced at first, has already been distributed, hence the so-called IPv4 IP addresses are progressively getting replaced with IPv6 addresses. Every domain that 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 groups of numbers from 1 to 255 divided by a dot, while in the IPv6 system it's called AAAA and it comprises of 8 groups of hexadecimal numbers i.e. this kind 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 is designed for a significantly bigger number of IPs than the IPv4 format.