Every device that is connected to the world wide web has a unique identifier named IP (Internet Protocol) address. This includes PCs, web servers, smart phones, switches, etc. The pool of IP addresses, which was introduced initially, is already distributed, therefore the so-called IPv4 IP addresses are gradually getting replaced with IPv6 addresses. Every domain name that 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 comprises of four sets of numbers from 1 to 255 divided by a dot, while in the IPv6 system it's called AAAA and it consists of 8 groups of hexadecimal numbers i.e. this type of records use numbers from 0 to 9 and letters from A to F. An example of an AAAA record is 2010:0c48:43d3:2142:1012:8c3a:2475:2435 and this format can handle a considerably larger number of IPs compared with the IPv4 format.