FirewallD is frontend controller for iptables that is used to filter network traffic. FirewalldD is not an iptables replacement, but it is a wrapper for iptables that is used to manage iptables rules. FirewallD provides an easy way to configure dynamic firewall rules that can be applied instantly without restarting any services. FirewallD provides both command line and graphical interfaces, and is available in most linux distributions.
Supports most linux distributions.
Load kernel modules automatically.
Easily integrates with Puppet.
Provides both command-line and graphical user interface.
Supports IPv4, IPv6 and NAT.
Predefined list of services and zones.
In this tutorial, we will learn how to setup firewalld and see some useful firewalld rules to configure your server using command line.
A server running CentOS-7 operating system.
A Non-root user account with sudo privilege set up on your server.
The firewalld package is installed by default in CentOS-7. If not installed, you can easily install it by running the following command:
sudo yum install firewalld
Once firewalld is installed, you will need to stop iptables service, if it is running.
You can stop and mask the iptables service with the following command:
The firewalld manages groups of rules using zones. Firewalld zones are predefined rulesets for various trust levels for a specific location. Once you have enabled firewalld first time, Public will be the default zone. You can apply zones to different network interface such as internal network and internet.
To view the default zone, run the following command:
The firewall configuration of the main services such as httpd, ftp, dhcp, etc comes in the /usr/lib/firewalld/services directory. It is also possible to add your own custom services to /etc/firewalld/services directory.
For example, HAProxy service is not available in the /usr/lib/firewalld/services directory. You can create your own haproxy service by creating /etc/firewalld/services/haproxy.xml file.
sudo nano /etc/firewalld/services/haproxy.xml
Add the following lines:
Now, add the HAProxy service to the default zone permanently and reload the firewall configuration:
I hope now that you should have a very good knowledge of how to configure and use firewalld service on your system. You can also use firewalld in your virtual lab environment to test firewalld with all parameters.
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