firewall-cmd is a command line interface for firewalld, a popular firewall software for Linux systems. Firewalld offers many useful features and is often employed by many Linux system administrators to manage their networks & systems. While using firewall-cmd you may get an error ‘firewall-cmd command not found’. In this article, we will learn how to fix this issue.
How to Fix “firewall-cmd: command not found” error in Linux
This error mainly occurs because firewalld tool is not installed on your system, not properly installed on your system, or is outdated. Many systems, especially cloud virtual machines, have firewalld installed but not firewall-cmd. So when you try to configure firewall using firewall-cmd, you may get this error.
The solution is to install firewalld on your system. It already contains firewall-cmd packaged into it. Open terminal and run the following command for this purpose. If you have already installed it, you can skip this step.
$ sudo yum install firewalld
Next, run the following commands to start and enable autostart for firewalld, at system boot.
$ sudo systemctl start firewalld $ sudo systemctl enable firewalld $ sudo systemctl status firewalld
Once you have installed firewalld, you can use the following commands to open ports, e.g. port 80, and reload configuration to apply changes. Please note, we are using firewall-cmd command to manage ports.
$ sudo firewall-cmd --zone=public --add-port=80/tcp --permanent $ sudo firewall-cmd --reload
Similarly, here are the commands to block ports.
$ sudo firewall-cmd --zone=public --remove-port=80/tcp --permanent $ sudo firewall-cmd --reload
In this article, we have learnt how to fix ‘firewall-cmd: command not found’.
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