Debian 13 Chrony Not Syncing Time With NTP Servers

📖 ~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 causes auth failures, certificate issues, and inconsistent logs.

Environment & Reproduction

Seen when NTP egress is blocked or peers are misconfigured.

Root Cause Analysis

Chrony cannot reach valid upstream sources or source list is invalid.

Quick Triage

Check chrony source reachability and leap status.

Step-by-Step Diagnosis

Inspect chrony logs and network path to UDP 123.

Solution – Primary Fix

Set approved NTP servers and restart chrony.

Solution – Alternative Approaches

Use `systemd-timesyncd` on simpler hosts with limited requirements.

Verification & Acceptance Criteria

Chrony reports synchronized state and low offset values.

Rollback Plan

Restore previous chrony config if new source policy fails.

Prevention & Hardening

Monitor drift and source reachability across all nodes.

Related Errors & Cross-Refs

Related to APT validity errors and Kerberos clock skew failures.

Related tutorial: View the step-by-step tutorial for Debian 13.

View all Debian 13 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Chrony operational best practices for Debian systems.