[ntp:questions] Meinberg NTP Software--Time Accuracy

Martin Burnicki martin.burnicki at meinberg.de
Tue Jun 23 12:32:22 UTC 2009

W. eWatson wrote:
> Martin Burnicki wrote:
>> David J Taylor wrote:
>>> W. eWatson wrote:
>>> []
>>>> I set drift.conf as above for Win2000.
>>>>   server 0.us.pool.ntp.org preempt iburst
>>>> but do not believe the PC clock is in synch with accurate time. After
>>>> 30-60 seconds they looked 3 sec apart.
>>> The Meinberg package is based in NTP 4.2.4, and mau not support the
>>> "preempt" keyword.  Try the following in your ntp.conf file:
>>>    server 0.us.pool.ntp.org iburst
>>>    server 1.us.pool.ntp.org iburst
>>>    server 2.us.pool.ntp.org iburst
>>>    server 3.us.pool.ntp.org iburst
>> Whether pool servers are being configured or a dedicated USNO server, is
>> a question of policy, but should not make a difference for this problem.
>> However, having a look at the contents of the OP's ntp.conf file shows an
>> entry:
>> # Use specific NTP servers
>> server tick.usno.nav.mil iburst
>> If you look at the spelling then you see there's a typo:
>> tick.usno.nav.mil  can not be resolved, this should read:
>> tick.usno.navy.mil
>> So the name of the upstream server is simply invalid, and thus ntpd can
>> not sync to it. And, if you'd misspell the names of the pool servers, the
>> pool server would not work, either.
>> This also explains why "ntpq -p" prints "No association ID's returned"
>> (as reported by the OP in an earlier post), and I'm sure if the OP had
>> done as I earlier suggested and had had a look into the Windows
>> application event log he would have seen an appropriate error message
>> which leads into the right direction.
>> Martin
> It looks like pulling the preempt, did the trick. It "looks" like the two
> sources, NTP and my Radio Shack atomic clock, are very close. Too bad one
> of them doesn't beep every five seconds.

Hm, I doubt any "preempt" helps if the name of the upstream server is
misspelled in the config file.

On the other hand, I'm sure you also get it working as expected without
"preempt" if you write the name of the upstream server correctly ;-)

> Is there a primer for NTP?
> I have a number of colleagues who are working with the same equipment and
> software, but are operaing with Linux or Apple. Does some implementation
> like Meinberg exist for them?  Where would they find it?

The required basic configuration is the same as for Windows.

You need to end up with one or more lines like

server <hostname> iburst

in the ntp.conf file. Unfortunately different Linux distributions and
distribution versions come with different ways to specify the upstream

Under SuSE/openSUSE you can use the YaST tool to configure NTP. Other
distros may provide specific ways to do so (e.g. under CentOS there's a
file /etc/ntp/ntpservers which specified 3 centos pool servers by default.

If you run a DHCP server then you can also let the DHCP server distribute
the IP addresses of some NTP servers. Please note the DHCP clients shipped
with Linux and not NTP add those entries to the ntp.conf file. AFAIK this
does not work under Windows, and I don't know about Apple.

Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont

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