Every single device that 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 IPs, that was introduced originally, is already distributed, therefore the so-called IPv4 IP addresses are gradually getting replaced with IPv6 addresses. Every domain which opens an internet site comes with an IP record, which is the address of the server where it's hosted. With the IPv4 system, the record is called A and it consists of four sets of numbers from 1 to 255 divided by a dot, while with the IPv6 system it is called AAAA and it is made up of eight sets of hexadecimal numbers i.e. this type 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 supports a significantly greater number of IPs in comparison with the IPv4 format.