System Administration

SELinux Troubleshooting

July 23, 2025
Security, Tutorials, System Administration
Selinux, Security, Linux, Rhel, Centos, Troubleshooting, System-Administration

SELinux Troubleshooting #

Here’s a little guide on how to find if SELinux is blocking something and how to add an exception to the policy.

SELinux Modes #

SELinux operates in three modes:

# Check SELinux status and mode
sestatus

Understanding the Three Modes #

  1. Enforcing: SELinux policy is enforced
  2. Permissive: SELinux policy violations are logged but not blocked
  3. Disabled: SELinux is completely disabled

Check if SELinux is the problem # 

# Temporarily set to permissive mode and test
setenforce 0
# Test your application
# If it works now, SELinux was blocking it
setenforce 1

Troubleshooting Workflow #

When an application fails and you are certain that SELinux is blocking it, e.g. you turned SELinux off or into permissive mode and the application worked, you can do the following: