Configure Windows 7 PC as NTP server.

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I am trying to configure a Windows 7 PC as an NTP server, but doesn't matter which config I try, the "w32tm /query /source" always returns the result to be "Local CMOS clock "
The PC is on my domain, but I have denied it access to read the network time policy, firewall is turned off on the PC.

What are my possible next steps?
What ports if any do I need to open on the physical firewall?

Does anyone have a config that has been tried tested and proven?

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Windows 7 PC as an NTP server
Windows 7 cannot be an NTP server without 3rd party software. Why in the world to you want to make it an NTP server when the domain already provides you one

This is what I have used before
Dr. KlahnPrincipal Software Engineer

In my own opinion, it is imprudent to configure any system as an NTP server unless (a) there is a requirement for time precise to the millisecond from UTC, and (b) the server has commercial-grade timekeeping hardware attached.   A single consumer-grade GPS receiver with a serial interface as a reference is not good enough, two is not much better, and configuring NTP service using a PC's internal BIOS clock as the reference makes no sense at all as these can (and do) drift up to several seconds a day.

There are many stratum 2 NTP servers on the internet, freely available to the public.  It is not sensible to take the time and effort to configure and maintain a local NTP server from consumer-grade hardware that is not as good as the timekeeping available for free over the internet.
Top DocSystems Administrator


@Shaun -
Your solution worked.
This video link also help me in configuring the tool.
Thanks for the assist.

@Dr. Klahn -
Thanks for the input.
Adam BrownSenior Systems Admin
Top Expert 2010

A single consumer-grade GPS receiver with a serial interface as a reference is not good enough

I'm with you up to this...A GPS receiver will provide accurate *enough* time for the vast majority of purposes. The primary function met by NTP is the common need for controlling numerous computer clocks that need to have the same time set. Any NTP capable device will handle that function effectively. There are few reasons for making sure systems all have the same time *and* aren't drifting away from true UTC across an interval that isn't provided by just about every solution short of a dedicated atomic clock.

That said, there are very few reasons to *not* use the reputable public NTP servers. Among those is a need for NTP authentication, which is a serious security concern, and something that is only available from commercial grade solutions. Granted, the cost of such a solution isn't justifiable for any environment that isn't under strict regulatory compliance standards.
Top DocSystems Administrator


I am agreeing with you all on the matter.
But my reason for wanting to configure an ntp server is that I just wanted to provide a central time for my NVRs which are isolated from the internet.

SO my plan was to configure NTP server on my windows 7 PC to provide time syncing among all devices.

that windows 7 PC is also isolated from the internet, and to accomplish the purpose, I would only allow the single port through the firewall to the internet time provider.

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