Every device which is connected to the web has a unique identifier named IP (Internet Protocol) address. This includes computer systems, web servers, smartphones, switches, etc. The pool of IP addresses, that was introduced at first, is already distributed, therefore the so-called IPv4 IP addresses are steadily getting replaced with IPv6 addresses. Every domain that opens a website 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 comprised of four sets of numbers from 1 to 255 split up by a dot, while with the IPv6 system it is called AAAA and it comprises of eight sets of hexadecimal numbers i.e. this sort 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 works with a substantially greater number of IPs compared with the IPv4 format.