CentOS Stream 9 – Common Problem 227 – Diagnosis and Fix

📖 ~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

httpd fails to bind non-standard port

Environment & Reproduction

After moving Apache to a custom port without SELinux labels.

Root Cause Analysis

http_port_t lacks the new port so targeted policy denies bind.

Quick Triage

Check denials with ausearch -m AVC -ts recent and getsebool -a | grep httpd.

Step-by-Step Diagnosis

Run: sudo ausearch -m AVC | audit2why; semanage port -l | grep http_port_t.

Solution – Primary Fix

sudo semanage port -a -t http_port_t -p tcp ; sudo systemctl restart httpd.

Solution – Alternative Approaches

Use setsebool httpd_can_network_connect on for outbound, or relabel the listening socket.

Verification & Acceptance Criteria

httpd starts cleanly and ss -ltnp shows the new port owned by httpd.

Rollback Plan

semanage port -d -t http_port_t -p tcp and revert httpd.conf Listen directive.

Prevention & Hardening

Codify port labels in an Ansible role and pre-validate with audit2allow.

Related Errors & Cross-Refs

Pairs with permission denied and Address already in use errors.

Related tutorial: View the step-by-step tutorial for centos-stream-9.

View all centos-stream-9 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

SELinux Notebook and httpd_selinux(8) man page.