Each device that's connected to the Internet has a unique identifier named IP (Internet Protocol) address. This includes computer systems, web servers, smart phones, switches, etcetera. The pool of IPs, which was introduced originally, has already been distributed, so the so-called IPv4 IP addresses are steadily being replaced with IPv6 addresses. Every domain that opens a site has an IP record, which is the address of the server where it is hosted. Using the IPv4 system, the record is called A and it is made up of 4 sets of numbers from 1 to 255 divided by a dot, while in the IPv6 system it's called AAAA and it consists of 8 sets of hexadecimal numbers i.e. this kind 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 works with a significantly bigger amount of IPs in comparison with the IPv4 format.