Every device that's connected to the Internet has a distinctive identifier named IP (Internet Protocol) address. This includes PCs, web servers, smart phones, switches, etcetera. The pool of addresses, which was introduced originally, is already distributed, hence the so-called IPv4 IP addresses are gradually being replaced with IPv6 addresses. Every domain name which opens an internet site has 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 comprises of four groups of numbers from 1 to 255 separated using a dot, while in the IPv6 system it's called AAAA and it is comprised of 8 sets 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 supports a significantly larger amount of IPs compared with the IPv4 format.