Network Security
How networks actually work, and how to secure them, from IP addresses to firewalls to VPNs.
1. What is a Network, Really?
IP addresses, packets, and routers, the basics everything else in this subject builds on.
2. The OSI Model, Just Enough to Be Useful
A 7-layer way of thinking about networking that shows up constantly in security tooling and job interviews.
3. TCP vs UDP
The two ways data actually travels across a network, and why the choice matters.
4. Firewalls, Deeper Than the Basics
Stateless vs stateful filtering, and what a real firewall rule actually looks like.
5. VPNs and Why They Matter
Encrypting your traffic and hiding it inside a trusted tunnel.
6. Wireless Network Security
Why WPA3 matters, and the WiFi habits that actually protect you.
7. Network Scanning & Reconnaissance
How security professionals map out a network, and why the same tools serve both attackers and defenders.
8. Securing a Home or Small Office Network
A practical checklist that closes most of the common ways a small network gets compromised.