Every single device which is connected to the web has a unique identifier known as IP (Internet Protocol) address. This includes personal computers, web servers, smart phones, switches, etc. The pool of IP addresses, which was introduced at first, is already distributed, therefore the so-called IPv4 IP addresses are progressively getting replaced with IPv6 addresses. Every domain name that opens an internet site comes with an IP record, which is the address of the server where it is hosted. With the IPv4 system, the record is called A and it comprises of 4 groups of numbers from 1 to 255 divided by a dot, while in the IPv6 system it is called AAAA and it is comprised 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 works with a significantly greater number of IPs than the IPv4 format.