Each device that's connected to the web has a unique identifier referred to as IP (Internet Protocol) address. This includes personal computers, web servers, smart phones, switches, and so on. The pool of IP addresses, that was introduced at first, has been distributed, hence the so-called IPv4 IP addresses are progressively getting replaced with IPv6 addresses. Every domain which opens a website comes with an IP record, which is the address of the server where it's hosted. Using the IPv4 system, the record is called A and it is comprised of four sets of numbers from 1 to 255 divided using a dot, while with the IPv6 system it's called AAAA and it is made up of eight sets of hexadecimal numbers i.e. this sort of records use digits 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 substantially bigger amount of IPs in comparison with the IPv4 format.