Support Support Downloads Knowledge Base Juniper Support Portal Community

Knowledge Base

Search our Knowledge Base sites to find answers to your questions.

Ask All Knowledge Base Sites All Knowledge Base Sites JunosE Defect (KA)Knowledge BaseSecurity AdvisoriesTechnical BulletinsTechnotes Sign in to display secure content and recently viewed articles

Do Junos OS platforms respond to the "leap-second calculations"?



Article ID: KB12979 KB Last Updated: 11 Jun 2015Version: 3.0

This article describes how Junos OS platforms support "leap-second calculations."


All Juniper platforms that run Junos OS support the "leap-second" adjustment.

If the NTP server is aware of the leap-second calculations, then the Junos device will also add the 1-second delay by default. Nothing specific needs to be done on the Junos devices to enable this.

NTP automatic time synchronization works only if the times on the two systems are very close. Very close means between 128 milliseconds and 128 seconds apart.

Beyond this, the time is not changed at all. If the time is more than 1000 seconds off, NTP records the following system log message:

Mar 16 16:41:41 5htp-fxp0 xntpd[28243]: time error 4217 over 1000 seconds; set clock manually

If the time is this far off, you need to reset the clock manually:

admin@router1# set date ntp

This command uses the NTP servers that you have configured. You do not have to reboot the router for the new time to take effect.

Juniper's PTP (Precision Time Protocol) implementation in Junos OS can detect and forward leap-second changes from the head node of synchronization (reference) to the end nodes (base stations/servers).

Related Links

Comment on this article > Affected Products Browse the Knowledge Base for more articles related to these product categories. Select a category to begin.

Getting Up and Running with Junos

Getting Up and Running with Junos Security Alerts and Vulnerabilities Product Alerts and Software Release Notices Problem Report (PR) Search Tool EOL Notices and Bulletins JTAC User Guide Customer Care User Guide Pathfinder SRX High Availability Configurator SRX VPN Configurator Training Courses and Videos End User Licence Agreement Global Search