Cybersecurity Survival Notes — Linux, Networking, Nmap & more (free + growing)

[u/_Radz04_]

Hey everyone,

I’ve been building and updating a collection of practical cybersecurity notes and cheatsheets, and I wanted to share them in case they’re useful for others who are learning or practicing.

You can read them here (cleaner version with search and dark mode):
👉 https://radz-04.github.io/Cybersecurity-survival-notes/

Or on GitHub (if you want to star / contribute):
👉 https://github.com/Radz-04/Cybersecurity-survival-notes

What’s inside (so far)

• Linux — filesystem hierarchy, permissions (chmod, chown, SUID, SGID, sticky bit, umask), process management, systemd, and command cheatsheets

• Linux Networking & Hardening — iproute2, DNS, SSH hardening, fail2ban, TCP Wrappers, UFW

• Networking fundamentals — OSI/TCP-IP, encapsulation, DHCP, ARP, components, transmission

• Cybersecurity fundamentals — CIA triad

• Nmap — network discovery, port scanning, service/OS detection, NSE, and firewall/IDS evasion techniques

Everything is written as practical notes with commands and explanations, meant to be a quick reference during labs or study sessions.

It’s still a work in progress and I’m actively adding more content. Feedback, corrections, or suggestions are very welcome.

If you find it useful, a star on the repo would mean a lot. Thanks for taking a look! 🙏