Linux Firewall Gently - Firewalld: Second Edition

By Sujata Biswas

Is your Linux server really protected, or is the firewall just "probably fine"?

Linux Firewall Gently teaches you firewalld the way a patient colleague would: one small step at a time, with plain-English analogies, real screenshots and commands you can type and test yourself. No jargon walls. No guessing.

NEW IN THE 2026 UPDATE

CentOS 7 is gone, but your skills don't have to be. This updated edition keeps every original lesson and adds ten brand-new chapters for today's systems:

- Firewalld on AlmaLinux, Rocky Linux, RHEL, Fedora and Ubuntu
- How firewalld works with nftables under the hood
- Policies: controlling traffic between zones
- Troubleshooting from Windows 11 (PowerShell) and Linux
- A modern Squid proxy setup, including SELinux
- Docker, Podman and virtual machines
- Managing firewalld from a browser with Cockpit
- Cloud servers and security groups: layers of defence
- A hardening checklist and the ten most common mistakes
- A one-page firewall-cmd command cheat sheet

WHAT YOU WILL LEARN

- Install, start and check firewalld, and understand zones in minutes
- Allow services and ports, temporarily or permanently (and never lose a rule on reboot again)
- Prove whether a port is blocked, using telnet, PowerShell and Linux tools
- Build a multi-zone firewall, rich rules, port forwarding, masquerading and NAT
- Read firewalld's XML configuration files with confidence
- Use IP sets and Fail2Ban to block brute-force attackers
- Log denied traffic and find out what your firewall is really doing

A real project, not just theory. You will install a Squid proxy server, open its port, and troubleshoot a "the Internet is not working" ticket from a Windows machine, exactly as it happens in real life.

WHO IS THIS BOOK FOR?

System administrators, DevOps and cloud beginners, Linux students, help-desk and support engineers, and anyone preparing for Linux certification who wants to finally understand the firewall.

ABOUT THE AUTHOR

Sujata Biswas has worked in IT for over three decades and writes practical, beginner-friendly Linux and IT guides based on real troubleshooting experience.

Scroll up and click "Buy now" to secure your server the gentle way.

• Format: Paperback
• Language: English
• ISBN: B0BXNKPW1P
• ISBN13: 9798386705732
• Release Date: March 2023
• Publisher: Independently Published
• Length: 72 Pages
• Weight: 0.42 lbs.
• Dimensions: 0.1" x 8.5" x 11.0"