SELinux is enabled by default on some Linux distributions including Oracle Linux, RHEL, CentOS, and Fedora. Use the sestatus command to determine if SELinux is enabled on your distribution:
$> sestatus
SELinux status: enabled
SELinuxfs mount: /sys/fs/selinux
SELinux root directory: /etc/selinux
Loaded policy name: targeted
Current mode: enforcing
Mode from config file: enforcing
Policy MLS status: enabled
Policy deny_unknown status: allowed
Memory protection checking: actual (secure)
Max kernel policy version: 31
If SELinux is disabled or the sestatus command is not found, refer to your distribution's SELinux documentation for guidance before enabling SELinux.