How to Check NTP on Ubuntu 26.04

Knowing how to perform an NTP check on Ubuntu 26.04 is essential for any administrator who needs accurate, synchronized system time. Ubuntu 26.04 Resolute Raccoon ships with Chrony as the default NTP daemon, replacing the older systemd-timesyncd. Chrony provides faster synchronization, better accuracy, and supports Network Time Security (NTS) out of the box. This guide walks you through every method to verify NTP status, interpret synchronization output, and diagnose common time-sync issues on Ubuntu 26.04.

Software Requirements

TL;DR

Check Chrony Service Status

The first step in any NTP check on Ubuntu 26.04 is confirming that the Chrony service is running. Unlike older Ubuntu releases that used systemd-timesyncd, Ubuntu 26.04 uses Chrony as the default NTP daemon. Therefore, you should query the chronyd service:

$ systemctl status chrony

A healthy output shows the service as active (running). Additionally, you will see recent log entries showing NTP source selection and clock adjustments. If the service is not running, start it with:

$ sudo systemctl start chrony

To ensure Chrony starts automatically on every boot, enable it as well:

$ sudo systemctl enable chrony

Check NTP Synchronization with chronyc tracking

The most detailed way to perform an NTP check on Ubuntu 26.04 is the chronyc tracking command. This command queries the running Chrony daemon and displays the current synchronization state of the system clock:

$ chronyc tracking

The output contains several important fields. Understanding each one helps you assess whether your system time is healthy:

Consequently, if the Reference ID shows 7F7F0101 (the loopback address), Chrony is not synchronized to any external source and is operating in free-running mode. In that case, check your network connectivity and NTP server configuration.

Check NTP Sources

To see which NTP servers Chrony is communicating with, use the chronyc sources command. The -v flag adds a descriptive header that makes the output easier to read:

$ chronyc sources -v

Each row represents one configured NTP source. The output uses two symbol columns before the server name. The first column indicates the source mode, and the second indicates the source state:

The remaining columns provide additional detail about each source:

Ubuntu 26.04 configures Chrony to use the ntp.ubuntu.com pool, which resolves to Canonical NTS servers (e.g. ntp-nts-*.ps5.canonical.com, ntp-nts-*.ps6.canonical.com). Therefore, you should normally see several servers listed with ^* or ^+ symbols and a Reach value of 377, confirming full reachability. The NTP configuration file at /etc/chrony/chrony.conf controls which pools are queried.

Check NTP Source Statistics

For a more thorough NTP check on Ubuntu 26.04, the chronyc sourcestats command provides statistical data about each NTP source over time:

$ chronyc sourcestats -v

This command is useful for evaluating the long-term reliability of each source. The key columns are:

Moreover, a low Std Dev value across your sources indicates that Chrony has stable, consistent data to work with, resulting in accurate time synchronization. If you are configuring a dedicated NTP server, reviewing sourcestats output is a critical part of validating its reliability.

Check Time Sync with timedatectl

The timedatectl command provides a high-level summary of the system time configuration and is a quick way to confirm NTP is active on Ubuntu 26.04:

$ timedatectl

The output shows several fields relevant to NTP verification:

If System clock synchronized shows no, the system has not yet completed its first successful synchronization. This can happen shortly after boot, as Chrony needs a few polling cycles to establish sync. Additionally, network issues or misconfigured NTP sources can prevent synchronization from completing. In that case, check your NTP settings and verify that the configured servers are reachable.

Verify NTS (Network Time Security)

Ubuntu 26.04 enables Network Time Security (NTS) by default in Chrony, providing authenticated and encrypted NTP communication. To verify that NTS is functioning correctly, run chronyc ntpdata piped through grep to isolate the authentication field (the full output is lengthy):

$ sudo chronyc ntpdata | grep -i auth

A line reading Authenticated : Yes for each source confirms that the NTP exchanges are authenticated via NTS. This is an important security verification, particularly for servers handling sensitive workloads or compliance requirements.

Furthermore, you can check the authentication details for all sources at once using the authdata subcommand. The -n flag suppresses DNS resolution, showing IP addresses instead of hostnames:

$ sudo chronyc -n authdata

The output columns are:

For more background on how Chrony is set up on this release, refer to the NTP client configuration guide.

Check NTP Logs

Chrony writes synchronization events to the system journal. Reviewing these logs is useful when troubleshooting intermittent sync failures or auditing time accuracy over a period. To view recent Chrony log entries, run:

$ journalctl -u chrony --since "1 hour ago"

You can extend the time range to audit a longer period. For example, to review the last 24 hours:

$ journalctl -u chrony --since "24 hours ago"

Key log messages to look for include:

1. Selected source: Indicates Chrony has chosen a new reference NTP source. Normal during startup and network changes.
2. System clock wrong by X seconds: Appears when Chrony detects a large initial offset and steps the clock to correct it quickly, rather than gradually slewing it.
3. System clock TAI offset set to X seconds: Logged on every startup. Confirms Chrony has loaded the leap second list from /usr/share/zoneinfo/leap-seconds.list.
4. Could not send to server: Indicates a connectivity problem with one of the configured NTP pool servers. Check network access if this appears repeatedly.

Additionally, if you have configured Chrony to write its own log files (via the logdir and log directives in /etc/chrony/chrony.conf), you can inspect them directly under the configured log directory, typically /var/log/chrony/.

Conclusion

Performing an NTP check on Ubuntu 26.04 is straightforward with the Chrony toolset. The combination of chronyc tracking, chronyc sources -v, chronyc sourcestats, and timedatectl gives you complete visibility into the NTP synchronization state of your system. Ubuntu 26.04 defaults to Chrony with NTS-enabled pool servers, providing both accurate and secure time synchronization out of the box. Whether you are verifying a desktop workstation or a production server, these commands cover every aspect of NTP verification. For further configuration, see the NTP guide for Ubuntu 26.04.

Frequently Asked Questions

1. Why is systemd-timesyncd not available on Ubuntu 26.04? Ubuntu 26.04 replaced systemd-timesyncd with Chrony as the default NTP daemon. Chrony offers superior synchronization accuracy, faster convergence after network disruptions, and native NTS support. The systemd-timesyncd package is not installed by default on this release.
2. How do I know if my system clock is actually synchronized? Run timedatectl and check that System clock synchronized shows yes and NTP service shows active. Additionally, run chronyc tracking and confirm the Reference ID is a valid NTP server address, not the loopback address 7F7F0101.
3. What does it mean when chronyc sources shows a ‘?’ symbol next to a server? A ? symbol means Chrony cannot reach that NTP source. This can indicate a DNS resolution failure, firewall blocking UDP port 123, or a network connectivity issue. Check that the server hostname resolves correctly and that outbound UDP port 123 is not blocked by a firewall rule.
4. How accurate is NTP synchronization with Chrony on Ubuntu 26.04? Under normal network conditions, Chrony typically achieves sub-millisecond accuracy when using pool servers. The chronyc tracking output shows the current System time offset. Offsets of less than 10 milliseconds are considered good for general use. Hardware timestamping or PPS sources can achieve microsecond-level accuracy if required.
5. Can I use chronyc commands without sudo? Most read-only chronyc commands such as tracking, sources, and sourcestats can be run as a regular user without sudo. However, chronyc ntpdata and chronyc authdata require sudo. Commands that modify Chrony configuration or force actions (such as chronyc makestep) also require root privileges.