SELinux Blocks Custom App Port Binding

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

Service fails to bind to non-default TCP port due to SELinux policy.

Environment & Reproduction

systemctl restart fails and application logs report permission denied on bind.

Root Cause Analysis

The chosen port is not labeled for the service domain in SELinux.

Quick Triage

Compare configured port with allowed SELinux port mappings.

Step-by-Step Diagnosis

Run semanage port -l, ausearch -m AVC, systemctl status, and journalctl -u .

Solution – Primary Fix

Add or modify SELinux port mapping with semanage, open matching port in firewalld, restart service, and verify listener.

Solution – Alternative Approaches

Service binds successfully and remote clients connect.

Verification & Acceptance Criteria

Remove new port mapping if it conflicts with approved security policy.

Rollback Plan

Reserve and document custom ports with corresponding SELinux labels.

Prevention & Hardening

Enforce semanage and firewall-cmd tasks together in deployment playbooks.

Related Errors & Cross-Refs

SELinux enforcing mode is common in hardened RHEL 7 environments.

Related tutorial: View the step-by-step tutorial for rhel-7.

View all rhel-7 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Escalate for policy review when app requires broad or unusual port ranges.