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I have a raspberry pi hooked up to a local network where there is not internet acces. I have configured a computer to act as a timesever (windows timeservice). The timeserver has the ip 192.168.6.1 and the raspberry has the ip 192.168.6.83.

I have been reading about NTP and how to configure NTP. My configuration file (/etc/ntp.conf) looks like:

tinker panic 0
server 192.168.6.1 prefer true iburst

driftfile /var/lib/ntp/ntp.drift
logfile /var/log/ntp.log

minpoll 4
maxpoll 5

The output of the "ntpq -pn" command is:

    remote         refid      st t  when  poll reach    delay    offset  jitter
===============================================================================
192.168.6.1    192.168.6.82    3 u    23   64      3    0.652   1836879   2.136

There is a large offset but if I understood it correctly this shouldn't matter because of the 'tinker panic 0' line in the configuration file.

I know the server is working correctly because I can sync the right time with the command:

sudo sntp -s 192.168.6.1

I want the raspberry to sync with the server, no matter what the offset is. And it should go automatically. I want the raspberry to sync when it boots and then keep syncing.

I know about the post here but this uses the ntpdate which seems to be depreciated.

Rui F Ribeiro
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Steven
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2 Answers2

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To be able to sync with a Windows NTP, add 

tos maxdist 30

to the end of your /etc/ntp.conf and restart your NTP service.

From Why should I need a tweak to force VMware ESXi 5 to sync time with Windows NTP server

(quotation slightly changed in the Italics)

By default, an unsynced Windows server chooses a 10-second dispersion and adds to the dispersion on each poll interval that it remains in sync. A Linux ntpd, by default, does not accept any NTP reply with a root dispersion greater than 1.5 seconds.

Besides this, you also have to make changes to Windows.

Rui F Ribeiro
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  • @Steven What is the version of windows? – Rui F Ribeiro Feb 13 '18 at 15:03
  • Windows 10 Pro N – Steven Feb 13 '18 at 15:09
  • does this help? https://russlescai.wordpress.com/2013/01/07/setup-windows-8-as-ntp-time-server/ My other answer was wrong, whilst in windows 2k it was true, nowadays windows uses NTP – Rui F Ribeiro Feb 13 '18 at 15:22
  • It is a clear tutorial, but it is similar to tutorials I have found while trying to solve this problem. Your answer did point me in the right direction. I used [link] (http://www.satsignal.eu/ntp/setup.html) and now the raspberry does receive time updates. This would mean that there is something on the windows side that is not configured correct. The raspberry side was ok.

    Thanks anyway.

     – Steven Feb 13 '18 at 15:30
1

After some more trial and error I have found a solution to the problem. Most credit goes to @Rui F Ribeiro for pointing me in the right direction with his response (which he later deleted for being not correct). Because this did lead to a solution I am posting it.

Windows time service implements Simple-NTP (SNTP) by default and not NTP. As a result the ntp deamon won't be able to talk to the SNTP service.

Syncing by using the command sudo sntp -s 192.168.6.1 is a way that implements SNTP and therefore is able to set the time.

The solution for my problem was by using a NTP service (on windows) that can be found HERE (link points to a tutorial).

The program implements the NTP protocol on windows with the linux syntax. This service works out of the box when the computer on which it is installed is connected to the internet. I wanted to be able to sync the time even when the windows computer is not able to reach the time servers. Therefore I had to edit the ntp.conf file to include the following lines:

# add the Local clock
server 127.127.1.0
# Set stratum to a high level so that the clock is accepted
fudge 127.127.1.0 stratum 5

This resulted in the raspberry being able to sync with the windows computer (that may or may not be connected to the internet).

Steven
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