The DNS (Domain Name System) is a directory that lists all IP addresses on the Internet. Without a DNS server, the Internet, as we know it today, would not exist. To use an expression often used, the DNS server is a kind of IP address directory. Searching for the domain name works like the game “who is it? ». One asks a question, eliminates choices, and gradually progresses until finding the right answer, which in this case corresponds to an IP address or service.