Every single device that's connected to the web has a unique identifier known as IP (Internet Protocol) address. This includes computer systems, web servers, smart phones, switches, etc. The pool of IP addresses, which was introduced originally, has already been distributed, therefore the so-called IPv4 IP addresses are gradually getting replaced with IPv6 addresses. Every domain name which opens an internet 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 is made up of 4 sets of numbers from 1 to 255 split up with a dot, while in the IPv6 system it is called AAAA and it comprises of eight sets of hexadecimal numbers i.e. this sort 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 is designed for a significantly bigger amount of IPs compared with the IPv4 format.