Trying to enable firewalld in CentOS 7? We can help you.

Firewalld is a complete firewall solution available by default on CentOS and Fedora servers. Enabling it will manage the system’s iptables rules.

As a part of our Server Management Services, we assist our customers with several firewall queries.

Today, let’s see how our Support Engineers enable the firewalld on centos7 for our customers.

What is firewalld?

The firewall is one of the most important features of webservers. Firewalld is a complete firewall solution that manages the system’s iptables rules.

Moreover, it replaces iptables as the default firewall management tool. Normally, firewalld uses the concepts of zones and services.

So, it configures and manages using the firewall-cmd command-line utility. Also, it supports both IPv4 and IPv6 firewall settings.

Install and Enable Firewalld on Centos 7

Till now, we discussed firewalld in detail. Now let’s see how our Support Engineers install and enable the firewalld on centos7 servers.

Usually, Firewalld is installed by default on CentOS 7. However, if it’s not we install the package using the below command.

yum install firewalld

It successfully installs the firewalld service on the server.

Then we check if the firewalld service-disabled default on the server. To check so, we use the below command.

firewall-cmd --state

If the firewalld service is not activated on the server, it returns the result not running. Otherwise, we can see the running status.

To start the Firewalld service and enable it on boot, we use the below command:

systemctl start firewalld

systemctl enable firewalld

Also, to stop the firewalld service we run:

systemctl stop firewalld

Next, to disable the firewalld service on the server:

systemctl disable firewalld

Also to reload a FirewallD configuration, we use the below command:

firewall-cmd --reload

These are the techniques that can help to start, stop, disable, and enable the firewalld service.

[Couldn’t enable firewalld? We’ll help you]

Common errors while we Enable firewalld in Centos 7

Moving ahead, let us have a look at a few common errors.

• firewall-cmd: command not found

While trying to configure firewall rules on a server, the following error was received:

# firewall-cmd --zone=public --add-port=8080/tcp --permanent
firewall-cmd: command not found

firewall-cmd is a command-line front-end for firewalld (firewalld daemon), a dynamic firewall management tool.

To fix this error, we need to install firewalld on RHEL/CentOS 7 using yum package manager as follows.

# yum install firewalld
# systemctl start firewalld
# systemctl enable firewalld
# systemctl status firewalld

• Failed to issue method call: Access denied

While trying to enable firewalld, one of our customers came across the following error:

# systemctl enable firewalld
Failed to issue method call: Access denied

This error occurs when we try to start or enable a service that is either not installed on the Linux system or we typed an incorrect service name.

We can obtain the list of services by typing:

# systemctl list-units --type=service

In order to resolve this we follow the below steps:

If the install is not available, run:

# yum install firewalld

Then we enable firewalld by typing:

# systemctl enable firewalld

In order to start firewalld run:

# systemctl start firewalld

In addition check for hanging firewalld processes.

For example,

root 16278 1 4 Jan 21 ? 00:00:00 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid

Kill them and then:

# yum reinstall firewalld
# service unmask firewalld
# service enable firewalld
# service start firewalld

[Stuck with any of the errors? We’d be happy to help you fix them]

Conclusion

In short, The firewall is one of the most important features of webservers. The firewalld supports both IPv4 and IPv6 firewall settings. Today, we saw how our Support Engineers enable firewalld on centos 7 servers for our customers.