How Network Communication Works
You’re probably already aware that cell phones don’t communicate directly with other cell phones, they communicate with cell towers who make a mesh network with other cell towers to bounce your call, text, or other data from tower to tower until it reaches its destination. But you may not know that the internet works in a similar fashion. In this section, I want to explain how modern digital communication works to help you understand how some of the tools and techniques in later sections protect your communications.
Your Phone is a Radio
Without getting too deep into the weeds, all wireless signals run on the electromagnetic spectrum. Remember ROYGBIV from school, aka the rainbow? This is electromagnetic radiation, the kind we know as “the visible light.” Believe it or not, this is the entirety of wireless signal. Radio, X-Ray, cell phones, wifi, they’re all just light waves carrying information around. The only thing that separates them is the frequency of the waves on the electromagnetic spectrum.
Wireless microphones, radios, cell phones, and even WiFi all falls under the “radio waves” section. All of these devices use the same basic technology to work and the only thing that keeps them from interfering with each other is that they operate on different sections of the radio frequencies.
Needless to say, your phone is pretty small, and trying to shoot out enough radio radiation to reach anywhere in the world would be extremely damaging to your health, and would require your phone to be literally massive, too big to be mobile. So instead, your small phone has a limited range, just enough to connect to larger towers which in turn relay the signal where it needs to go. You’ve experienced this limitation yourself whenever you lose reception in the middle of nowhere.
The Internet Works the Same Way
Whether it’s WiFi or a physical ethernet cable, the internet communicates mostly the same way as cell phones in the sense that your data jumps around from location to location before reaching its final destination rather than going straight to the destination. Once your data leaves your router, it basically jumps through a series of other routers to get to its destination. These routers are not owned by individuals, they’re owned by corporations and internet service providers (ISPs), but the principle is the same.
What is DNS?
DNS - which stands for Domain Name Server - is the address book of the internet. When you type "Amazon.com" into your browser, your computer doesn't understand that address. It contacts your DNS, who looks up that address and tells your browser "oh, that's 126.96.36.199," which your computer understands. Your computer contacts that address, and Amazon is displayed on your screen for you to browse. Most internet service and VPN providers have their own DNS, but you can actually change most devices to use alternate DNS resolvers. There's a lot of advantages to that. For one, most default DNS providers keep a log of the sites you ping, which then gets sold to data brokers and added to your profile. For another, many alternate DNS providers block known advertising domains or malware, meaning a safer and less frustrating experience online. PrivacyTools.io offers a great list of alternate DNS providers, and if you're unsure how to change your DNS, try doing a web search for the device or browser you're using plus "change DNS."
The basic principle to take away from this section is that no communication goes straight to its destination. Whether it's text, phone call, email, Netflix streaming, Google searches, what-have-you. All communications bounce from place to place, sometimes trading hands of companies and jurisdictions multiple times along the way. Your email to your friend across town might actually cross continents before arriving, and your text message to your friend in the store next door might bounce through several cell phone providers’ networks before reaching them. This kind of relaying ability has made data access ubiquitous and fast in most areas of the developed world, but it also opens you up to incredible risk in terms of protecting your data in transit: you risk having your data unknowingly read or copied or even altered by any number of organizations, companies, hackers, or other people who have access to it along it’s path, whether legitimate or not.