Bug ID 1680105: Using 'iburst' option is preferred when adding NTP servers.

Last Modified: Jun 19, 2025

Affected Product(s):
F5OS F5OS-A, F5OS-C, Velos(all modules)

Known Affected Versions:
F5OS-C 1.8.0

Fixed In:
F5OS-C 1.8.1

Opened: Sep 26, 2024

Severity: 3-Major

Symptoms

It's reported that sometimes system time drifts even with NTP server configured.

Impact

System time drift.

Conditions

This is a common occurrence among specific NTP servers.

Workaround

Use 'iburst' option. It helps making more reliable synchronization and initial accuracy with the server.

Fix Information

From 1.8.1 and later, If the default settings are not specified, the settings will automatically change to iburst=true and association-type=pool. The old NTP configurations, which have the default settings, will be updated to new default settings after the upgrade.. This change is relatively secure and is not likely to result in any problems.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips