Every device which is connected to the web has a unique identifier named IP (Internet Protocol) address. This includes PCs, web servers, smart phones, switches, etcetera. The pool of addresses, that was introduced initially, is already distributed, hence the so-called IPv4 IP addresses are progressively getting replaced with IPv6 addresses. Every domain name that opens a site comes with an IP record, that is the address of the server where it is hosted. Using the IPv4 system, the record is called A and it comprises of four sets of numbers from 1 to 255 divided with a dot, while in the IPv6 system it is called AAAA and it consists of 8 groups of hexadecimal numbers i.e. this sort of records use digits 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 works with a substantially larger number of IPs in comparison with the IPv4 format.