CentOS Stream 9 – Common Problem 248 – 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

Intermittent DNS lookup failures

Environment & Reproduction

systemd-resolved disabled but /etc/resolv.conf still symlinked.

Root Cause Analysis

Stub resolver socket 127.0.0.53 is not listening so queries fail.

Quick Triage

resolvectl status or ls -l /etc/resolv.conf.

Step-by-Step Diagnosis

Run: sudo resolvectl status; ls -l /etc/resolv.conf; ss -lnup | grep 53.

Solution – Primary Fix

sudo rm /etc/resolv.conf and let NetworkManager regenerate it directly.

Solution – Alternative Approaches

Re-enable systemd-resolved with systemctl enable –now systemd-resolved.

Verification & Acceptance Criteria

dig @127.0.0.1 a record resolves and resolvectl status shows servers.

Rollback Plan

Restore /etc/resolv.conf symlink to /run/systemd/resolve/stub-resolv.conf.

Prevention & Hardening

Pick one resolver strategy across the fleet and enforce via Ansible.

Related Errors & Cross-Refs

Pairs with NXDOMAIN spurious and connection timeout to internal services.

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

systemd-resolved docs and NetworkManager DNS section.