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CybersecurityStage 1

Leaving Athens

A network is just nodes and paths — the same whether it's roads or cables.

Overview

You're standing at the Port of Piraeus, the ancient harbor of Athens. Before you can travel anywhere, you need to understand the network of roads, ships, and planes that connect the world. A computer network works exactly the same way: devices (nodes) connected by paths (links), each able to send information to any other.

The ancient Greeks built road networks to move armies and trade goods. We build computer networks to move data. In both cases, the principles are identical: every node needs an address, every path has a direction, and information travels from source to destination by hopping through intermediate points.

Your mission begins here. Read the port map, understand how the network of routes connects Athens to the world, and find your path west — toward Santa Cruz, California.

Attack Flow

ATTACKER
Your Device
the starting node
SYSTEM
Local Network
your home/office LAN
TARGET
The Internet
global mesh of networks
RESULT
Destination Server
the ending node

Technical Deep-Dive

How Computer Networks Are Built

A network is a collection of devices (computers, phones, routers) connected by physical or wireless links. Each device is a node. Data travels as electrical signals over cables, or as radio waves over WiFi. The internet is just a global network of networks — millions of smaller networks all interconnected.

Networks are described by their topology: how nodes are arranged. A star topology has all devices connecting through a central hub. A mesh topology has devices connecting directly to each other. The internet uses a mesh-like topology so there's no single point of failure.

Checking your network connections on Linux/Mac

# See all network interfaces on your device
ip addr show          # Linux
ifconfig              # Mac/older Linux

# See which devices are on your local network
arp -a

# Trace the path data takes to reach a destination
traceroute google.com

Real-World Incident

The 2021 Facebook Outage — When a Network Loses Its Map

📅 October 4, 2021📍 Global — Facebook, Instagram, WhatsApp💥 3.5 billion users offline for 6 hours; $60M+ revenue loss

On October 4, 2021, Facebook's engineers made a routine configuration change that accidentally removed all the routing information telling the internet how to find Facebook's servers. Every road on their network map was erased simultaneously.

No one could reach Facebook, Instagram, or WhatsApp. Even Facebook's own engineers couldn't log in remotely to fix the problem — they had to physically drive to the data center and manually restore the routing tables. The network still existed; the map of how to traverse it was simply gone.

Timeline

1969ARPANET — first 4 nodes connected; the internet's ancestor born
1983TCP/IP adopted — all ARPANET nodes switch to the modern protocol
1991World Wide Web launched — the internet becomes navigable
2021Facebook BGP outage — 3.5B users offline when routing tables wiped

Key Takeaways

A network is nodes (devices) connected by links (cables/WiFi)

The internet is a network of networks — no single owner

Routing tables are the 'map' — lose the map, lose the network

Every device needs an address to send and receive data

References

Ready for the challenge?

Exploit the vulnerability in a simulated environment and capture the flag.