NTP Client Software

Network Time Protocol (NTP) is a client-server protocol. A client computer periodically requests timing information from a NTP server. The server responds to requests with timing information that the client can then use for synchronization purposes.

Most operating systems have built-in tools to allow computers to automatically synchronize their system clock. For most deployments, the built-in tools are fine. However, there are third-party tools readily available that can provide enhanced features and more resilient synchronization.

Publishers of NTP Client Software

There are a large number of publishers of NTP client software for various operating systems. Many are provided free of charge, some require a small fee.

Unix and Linux

The Network Time Protocol Project – NTPd
The NTP project is the official reference implementation of the Network Time Protocol. Source code can be downloaded for compilation on a host machine. However, most Linux distributions have pre-installed versions of the NTP daemon. The implementation provides numerous features, including authentication, redundancy and excellent stability. The source code is open source and can be downloaded and used free of charge.
http://www.ntp.org/downloads.html

OpenNTPD
OpenNTPD is an easy to use NTP client primarily developed as part of the OpenBSD project. The software is freely available under a BSD licence.
http://openntpd.com/

Chrony
Chronyd is a versatile implementation of a NTP client. It was developed to run satisfactorily under a wide-range of operating conditions. It performs well on virtual machines, congested networks or systems with intermittent network connectivity. The chronyd software is distributed under the GNU General Public License. Chrony is available for Linux, FreeBSD, NetBSD, macOS, and Solaris.
https://chrony.tuxfamily.org/

Microsoft Windows

Windows Time Service – w32time
The Windows Time Service (w32time) is the build-in client software provided by the Windows operating system. When peer to peer networking is deployed, w32time can be configured from the “Date and Time” applet. However, if domain networking is utilized, registry setting changes are required to configure the service.
https://docs.microsoft.com/en-us/windows-server/networking/windows-time-service/windows-time-service-tools-and-settings

The Network Time Protocol Project – NTPd
A port of the NTP project is also available for Windows operating systems. The NTP project is one of the the most comprehensive client solutions available and is highly recommended. It is also available free of charge on an open source licence.
http://www.ntp.org/downloads.html
http://norloff.org/ntp/

NIST Time Client
NIST is the US Department of Commerce National Institute of Standards and Technology. Nistime is a 32-bit client that runs in background and periodically queries a NTP server. The application is well documented by providing help links to explain various features.
https://www.nist.gov/pml/time-and-frequency-division/services/internet-time-service-its

A Selection of Other Windows NTP Client Software Publishers

http://www.beaglesoft.com/index.htm
http://www.bytefusion.com
http://www.mingham-smith.com/
http://www.timesynctool.com/
http://www.thinkman.com/

Mac OS X

Date & Time Preferences
Mac OS X has built-in tools for NTP time synchronization. Configuration is carried out from the “Date & Time” icon of the “System Preferences”

OpenNTPd
OpenNTPd is also available for the Mac OS X operating system, for details, see the link above.

NTP Client Software For Network Devices

NTP client software is often built into firewalls, routers, IP cameras and other network devices. Generally, configuration simply requires specifying the IP address or domain name of a NTP server for synchronization purposes.
https://www.cisco.com/c/en/us/support/docs/availability/high-availability/19643-ntpm.html
https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst4000/8-2glx/configuration/guide/ntp.html

Important Note

TimeTools has provided a list of NTP client software and associated web sites because the users of our web site may find them useful. The list is not complete. TimeTools does not in any way endorse any of the software that is listed on this page. We do not endorse any information presented on the listed web sites.

Additional Information

What is a Stratum 1 Time Server ?

Choosing a NTP Network Time Server

Andrew ShintonAbout Andrew Shinton
Andrew Shinton is the joint founder and Managing Director of TimeTools Limited. He has a BSc (Hons) degree in Computer Science. Andrew has over 20 years experience of GPS systems and Network Time Protocol (NTP) in the Time and Frequency Industry.

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