Each device that's connected to the web has a special identifier named IP (Internet Protocol) address. This includes computer systems, web servers, smart phones, switches, etcetera. The pool of IPs, that was introduced at first, has been distributed, hence the so-called IPv4 IP addresses are progressively being replaced with IPv6 addresses. Every domain name which opens a site comes with an IP record, which is the address of the server where it is hosted. When using the IPv4 system, the record is called A and it is comprised of 4 sets of numbers from 1 to 255 separated by a dot, while with the IPv6 system it is called AAAA and it comprises of eight groups of hexadecimal numbers i.e. this type 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 works with a substantially greater amount of IPs when compared with the IPv4 format.