Each device that's connected to the Internet has a unique identifier named IP (Internet Protocol) address. This includes computers, web servers, smart phones, switches, and so on. The pool of IP addresses, that was introduced originally, is already distributed, hence the so-called IPv4 IP addresses are progressively getting replaced with IPv6 addresses. Every domain which opens a site has an IP record, that is the address of the server where it's hosted. Using the IPv4 system, the record is called A and it is made up of four sets of numbers from 1 to 255 separated using a dot, while within 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. A good example of an AAAA record is 2010:0c48:43d3:2142:1012:8c3a:2475:2435 and this format supports a substantially greater amount of IPs compared with the IPv4 format.