Every single device which is connected to the Internet has a specific identifier called IP (Internet Protocol) address. This includes PCs, web servers, smart phones, switches, etcetera. The pool of IPs, which was introduced initially, has already been distributed, hence the so-called IPv4 IP addresses are slowly being replaced with IPv6 addresses. Every domain name that opens a website has an IP record, that is the address of the server where it is hosted. When using the IPv4 system, the record is called A and it is made up of 4 sets of numbers from 1 to 255 divided using a dot, while within the IPv6 system it's called AAAA and it is made up of eight sets of hexadecimal numbers i.e. this kind 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 works with a substantially bigger number of IPs compared with the IPv4 format.