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How to define a custom Firewalld zone

Firewalld is the default high-level firewall manager on the Red Hat family of distributions. One of its peculiarities is that it defines a series of so called firewall zones: each zone can be considered like a different level of trust and can be configured to allow traffic through a specific set of ports. While Firewalld comes with some predefined zones which can be easily examined and modified, sometimes we may want to create our custom zones from scratch.

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Viewing the iptables rules configured on our Linux system

Collection of basic Linux Firewall iptables rules

The purpose of this guide is to show some of the most common iptables commands for Linux systems. iptables is the firewall built into all Linux distributions. Even distros like Ubuntu, which utilizes ufw (uncomplicated firewall), and Red Hat, which utilizes firewalld still pass their commands to iptables and use it in the background.

Mastering iptables, or at least becoming familiar with some of the most basic commands, is essential for Linux administrators. Even casual Linux users can benefit from understanding the basics of the iptables firewall, since they may be required to apply some minor configurations to it at some point. Use some of the examples below to familiarize yourself with the iptables syntax and get an idea for how it works to protect your system.

WARNING
You should not apply iptables rules to a production system until you are somewhat familiar with how they work. Also be careful when applying rules to remote systems (a computer that you have established an SSH session with) because you can accidentally lock yourself out if you enter the wrong rule.

In this tutorial you will learn:

  • Collection of basic Linux firewall iptables rules
Viewing the iptables rules configured on our Linux system

Viewing the iptables rules configured on our Linux system

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