Each device which is connected to the Internet has a distinctive identifier named IP (Internet Protocol) address. This includes PCs, web servers, smart phones, switches, etc. The pool of IP addresses, that was introduced originally, is already distributed, so the so-called IPv4 IP addresses are progressively being replaced with IPv6 addresses. Every domain which opens a site comes with an IP record, which is the address of the server where it's hosted. Using the IPv4 system, the record is called A and it comprises of four groups of numbers from 1 to 255 separated using a dot, while with the IPv6 system it's called AAAA and it comprises of 8 sets of hexadecimal numbers i.e. this kind 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 considerably larger number of IPs when compared with the IPv4 format.