§ how it works
Each card below is a step-by-step SVG visualization of one protocol. Hit play, watch packets travel between devices, read what happens at each step, and follow a knowledge-base link when you want to go deeper.
These are drawn maps, the kind that stay in your head after one watch. They are not a simulation or a sandbox. To get hands-on, head to the lessons.
network · 6 steps
One URL → 12+ packets → 4 different protocols → ~100ms. The full chain from DNS to a rendered page in one overview. This is the finale: all the previous explainers in a single scene.
network · 12 steps
7 layers: what TCP adds, what IP adds, what Ethernet adds. Why "layers" are not theory but concrete bytes in a packet.
network · 5 steps
Where does the /24 in an IP address come from? Why are two hosts with similar IPs on the same network, while different ones are on different networks? It all comes down to bits.
network · 5 steps
A switch knows nothing at startup. In the first seconds of traffic it builds its own map, who is on which port, and stops flooding frames.
network · 5 steps
One physical switch, one cable plant, but logically split into several isolated broadcast domains. The magic is in a 4-byte tag.
network · 5 steps
You join Wi-Fi, and a second later you already have an IP. Where it comes from, who picks it, and why all of it works in 4 packets.
network · 4 steps
You know the IP, but how does the packet even leave the network card? First you need the neighbor's MAC. ARP does this with one broadcast.
network · 6 steps
The browser wants example.com, but the internet only understands IP addresses. Someone has to turn the name into a number, and a hierarchy of servers does it.
network · 5 steps
How does a packet reach Google from your laptop in 10-15 hops? Each router knows only "where to pass it next", and that is enough.
network · 5 steps
No packet comes back with the route inside it. To see the path, traceroute cleverly exploits TTL: it "kills" packets at each hop and collects the ICMP replies.
network · 5 steps
At home you have one public IP, but behind the router there are 10 devices, all going to the internet at the same time. The trick is that the router "remembers" who to send what.
network · 7 steps
Thousands of independent networks (AS) make up the internet. No one knows the whole map. Each AS just tells its neighbors what it can reach. Out of that comes all the routing on the planet.
network · 5 steps
1.1.1.1 answers fast from anywhere in the world because it physically lives in many places at once. The trick is BGP: each client lands on the nearest node.
network · 8 steps
Three-way handshake, then data, then four-way close. Why three handshakes, and why `ss` shows so many states after a connection closes.
network · 11 steps
When you look at `ss -tn`, you do not see only ESTABLISHED. SYN_SENT, FIN_WAIT_1, TIME_WAIT: what do they mean and why do they "hang"?
network · 8 steps
What does TCP do when a packet is lost? It does not wait long. Three "duplicate ACKs" in a row, and it resends right away without waiting for the timer.
network · 6 steps
How does TCP "know" how fast to send data? It does not. It tries faster and faster until it hits a wall. Then it cuts the rate in half and tries again.
network · 7 steps
The green padlock in the browser does not appear right away. Before it, a few packets pass where the two sides pick a cipher, check the certificate, and compute a shared key.
network · 7 steps
How does the browser "know" that example.com is real? A chain of signatures from the leaf cert through the intermediate up to the root, which is already built into the OS.