Each device that is connected to the world wide web has a unique identifier named IP (Internet Protocol) address. This includes personal computers, web servers, smart phones, switches, etc. The pool of IP addresses, that was introduced at first, is already distributed, therefore the so-called IPv4 IP addresses are steadily getting replaced with IPv6 addresses. Every domain which opens an internet site has an IP record, that is the address of the server where it's hosted. With the IPv4 system, the record is called A and it is made up of four sets of numbers from 1 to 255 divided using a dot, while with the IPv6 system it is called AAAA and it consists of eight groups of hexadecimal numbers i.e. this sort 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 greater amount of IPs in comparison with the IPv4 format.