conference logo

Playlist "35C3 Refreshing Memories"

How does the Internet work?

Peter Stuge

This Foundations talk explains the systems and protocols that make up the Internet, starting from a laptop with a Wi-Fi connection. No particular technical knowledge required.

Many consider "the Internet" a utility similar to electricity - and that's a great attitude! - but for most, "the Internet" only means access to a few centralized services offered by mega-corporations "for free", around which people build their entire social and professional lives.

Come along for a look behind the scenes of all those fancy websites, let's go through what the Internet actually is!

Knowing the difference between the network and services reachable through the network is perhaps more important than ever, because if we implicitly give service providers all the power by never asking for a public, utility-like network then that's the end of the Internet as we know it. Key word: Net neutrality.

So in this talk we will discover the network. In simple terms and without too much technical detail we'll start out with the "atom" of networks the packet, then cover the fundamental Internet Protocol (IPv4-only for simplicity), we'll try to answer what is a network? - not obvious it turns out, we'll look at where do IP addresses come from? and then we'll move on to the Internet cornerstone that is routing. We'll approach routing from the perhaps most well-known router - the wireless home router - and then look at how similar or dissimilar routers on the Internet are to that home router, leading us to a look at the routing protocol which constantly determines how our packets flow throughout the world.

Those are the basic building blocks of the Internet. Now for some delicious alphabet soup!

We'll take a step toward applications and compare UDP, TCP and SCTP, which are all used together with IP for most if not all end-user Internet communication.

Finally, we'll arrive at the most common applications, looking into how DNS (domain names), SMTP (sending email) and HTTP (web) work.

All of this is actually surprisingly simple and surprisingly old. None of it was built to be secure.

The goal is that you will gain an understanding of the structure of the Internet, that you will be able "see through" the browser, email client and web service facades, because now you know what's going on behind the scenes, and everything that's actually possible with a public utility network - far more than centralized consumption/you-are-our-product services.