Eli5: what prevents multiple websites from using the same domain name?

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If I make a website, like cookie.com, what exactly makes browsers direct to the “cookie.com” page I made? And what stops multiple “cookie.com”s from being hosted from different servers? The internet is decentralized so I just don’t understand how domain registration works at all.

On this note, what do the different domain extensions mean, and how are they created? It used to be 99% .net, .org and .com, but there’s like 50 trillion different ones now.

In: Technology

4 Answers

Anonymous 0 Comments

There are authoritative DNS entries that says which IP goes with cookie.com ( anybody else trying to use a different IP address won’t get any traffic.

Anonymous 0 Comments

Domain registration is the one relatively centralized parts of the internet.

An association called the Internet Corporation for Names and Numbers is the authority for all domain names. They create the domain extensions and grant the right to administer them to various parties called Top Level Domain administrators. They in turn either don’t sell (such as .gov domains), sell directly or allow companies to sell domains on the market.

Your computer, whenever it needs to find out who owns a domain name, will ask ICANN who administers say .com, then ask that admin who administers google.com, and it could go even further and ask whoever administers google.com who administers mail.google.con

Anonymous 0 Comments

That would be [ICANN](https://www.icann.org/) – Internet Corporation for Assigned Names and Numbers.

It’s not really just them, though. They are kind of the overseers of domain registry as a whole. When domain names are registered, they are checked for availability against the Domain Name System (DNS). DNS servers are all over, there’s not one single place, however they all typically share the same information.

When you type in a web address in your browser, you are asking a DNS server if they know who “cookie.com” is. That DNS server will go “Oh, yeah I know cookie.com! They’re at, I’ll connect you over to them.”

Because these DNS servers and domain name registrars all share the same information, you cannot register a domain with a name that is in use.

You could, however, set up your own DNS server with its own associations. You could say that cookie.com’s IP is, and then if you set that DNS server as your DNS provider, when you type cookie.com into your browser, you’d end up at google.

Anonymous 0 Comments

A similar thing to what is preventing you from having the number you like on your house or apartment building.
It’s regulated.
The ICANN is the international organization that coordinates who owns what.