Selinux Firewall Setting

As we do notice, now all Centos 7.x or Centos 8 OS is default loaded with Selinux Firewall Enabled.

To avoid your SSH access being blocked, please do remember to disable the setting inside your SSH.

How to disable SELinux on a CentOS 7 / RHEL 7 / Fedora Linux

The procedure to remove and disable SELinux security features is as follows:

1. Log in to your server
2. Check the current SELinux status, run: sestatus
3. To disable SELinux on CentOS 7 temporarily, run: sudo setenforce 0
4. Edit the /etc/selinux/config file and set the SELINUX to disabled
5. Reboot the Linux server
6. Verify it by running the sestatus and getenforce again

Let us see all commands, examples and usage in details.

How to find out SELinux status on CentOS 7

Run the following sestatus command sestatus

Another option is to run the following command to print the current mode of SELinux
getenforce
Enforcing
Another option is to runt the following cat command:
cat /etc/selinux/config
Sample outputs:

SELINUX=enforcing
SELINUXTYPE=targeted

Different types of security policy

The /etc/selinux/config file controls the state of SELinux on the system. SELINUX= can take one of these three values:

• enforcing – SELinux security policy is enforced.
• permissive – SELinux prints warnings instead of enforcing (disabled).
• disabled – No SELinux policy is loaded (disabled).

SELINUXTYPE= can take one of following:

• targeted – Targeted processes are protected.
• minimum – Modification of targeted policy. Only selected processes are protected.
• mls – Multi Level Security protection.

Warning: The author does not recommend disabling SELinux and is not responsible for security problems on your Linux-based server.

Disable SELinux

You can modify the mode SELinux is running in using the setenforce command. For example, to put SELinux in enforcing mode, run:
sudo setenforce Enforcing
sestatus
To put SELinux in permissive mode i.e. disabled mode:
sudo setenforce Permissive
sestatus
getenforce

Please note that is temporary solution to disable SELinux without rebooting the server and active for the current session only. Hence, use the following method for disabling SELinux forever.

Disabling SELinux permanently

Edit the /etc/selinux/config file, run:
sudo vi /etc/selinux/config
Set SELINUX to disabled:
SELINUX=disabled
Save and close the file in vi/vim. Reboot the Linux system:
sudo reboot
After reboot, make sure following commands gives Disabled output indicating that SELinux removed and disabled on your Linux server:
getenforce
sestatus