🟡 Medium   ⏱ 5–30 min  Last verified: 19 May 2026

📖 ~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

Clock drift grows, causing Kerberos/auth failures, TLS issues, and inconsistent distributed system timestamps.

Environment & Reproduction

RHEL 8 using chronyd in enterprise networks with restricted outbound UDP 123 or internal NTP tiers.

Root Cause Analysis

Invalid NTP sources, blocked firewall path, DNS resolution failure, or chronyd service misconfiguration.

Quick Triage

Check systemctl status chronyd, chronyc tracking, chronyc sources -v, and firewall-cmd rules for ntp service.

Step-by-Step Diagnosis

Review journalctl -u chronyd for source reachability and correction events.

Illustrative mockup for rhel-8 — rhel8-chronyc-sources-fail-01.webp
chronyc sources showing unreachable or unsynchronized peers — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Update /etc/chrony.conf with valid servers, open required firewall paths, restart via systemctl restart chronyd, and verify source reachability.

Still having issues? Our IT Solutions & Services team can diagnose and resolve this for you. Get in touch for a free consultation.

Illustrative mockup for rhel-8 — rhel8-chrony-sync-restored-01.webp
Chrony synchronized after source and firewall correction — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Confirm chronyc tracking shows normal stratum/offset and timedatectl indicates NTP synchronized status.

Verification & Acceptance Criteria

Temporarily point to internal fallback NTP server while upstream network issue is resolved.

Rollback Plan

Maintain redundant internal time sources and monitor chrony offset/stratum metrics continuously.

Prevention & Hardening

Time integrity is compliance critical for audit trails; enforce authenticated internal time hierarchy where required.

Deploy a health script that checks chronyc tracking and raises alert when leap status is not Normal.

Related tutorial: View the step-by-step tutorial for rhel-8.

View all rhel-8 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

chrony.conf(5), chronyc(1), and RHEL 8 system time synchronization documentation.

Need Expert Help?

If you cannot resolve this yourself, our team offers hands-on Server Management, Managed IT Services, and flexible Support Plans. Contact us today — we respond within one business day.