Ubuntu 24.04 LTS – system time not syncing with NTP – Fix & Prevention

📖 ~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 authentication, TLS, and scheduling anomalies across services.

Environment & Reproduction

Seen when outbound UDP/123 is blocked or NTP sources are unreachable.

timedatectl status

Root Cause Analysis

systemd-timesyncd cannot contact configured time servers or policy disables sync.

Quick Triage

Confirm service state and synchronization flag.

systemctl status systemd-timesyncd
timedatectl timesync-status

Step-by-Step Diagnosis

Inspect timesync logs and verify network path to NTP servers.

journalctl -u systemd-timesyncd -n 120
resolvectl query ntp.ubuntu.com

Solution – Primary Fix

Enable NTP synchronization and restart timesync service.

sudo timedatectl set-ntp true
sudo systemctl restart systemd-timesyncd
timedatectl status

Solution – Alternative Approaches

Set internal enterprise NTP sources in timesyncd.conf if required.

sudo sed -n '1,120p' /etc/systemd/timesyncd.conf

Verification & Acceptance Criteria

System reports synchronized time and stable offset values.

timedatectl status
timedatectl timesync-status

Rollback Plan

Revert to previous timesyncd config if new NTP source fails policy checks.

sudo cp /etc/systemd/timesyncd.conf.bak /etc/systemd/timesyncd.conf
sudo systemctl restart systemd-timesyncd

Prevention & Hardening

Monitor time offset and enforce outbound rules that allow approved NTP traffic.

Related Errors & Cross-Refs

Can surface as Kerberos skew errors and apt HTTPS certificate failures.

Related tutorial: View the step-by-step tutorial for Ubuntu 24.04 LTS.

View all Ubuntu 24.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Ubuntu time synchronization and systemd-timesyncd operational guidance.