[ntp:questions] Let ntp server not synchronize time from other servers

Martin Burnicki martin.burnicki at meinberg.de
Fri Aug 29 08:10:19 UTC 2008

Richard B. Gilbert wrote:
> WANG Cong wrote:
>> On Aug 28, 7:07 pm, Unruh <unruh-s... at physics.ubc.ca> wrote:
>>> WANG Cong <xiyou.wangc... at gmail.com> writes:
>>>> On Aug 28, 11:12 a.m, Martin Burnicki <martin.burni... at meinberg.de>
>>>> wrote:
>>>>> Hello WANG Cong,
>>>>> WANG Cong wrote:
>>>>>> Hello, experts!
>>>>>> Is there any way to configure my NTP server *not* to synchronize time
>>>>>> from other servers?
>>>>> Just don't put any server lines into your ntp.conf file ;-)
>>>> That's what I did. But it can't work, if there's no server lines, I
>>>> _always_ got:
>>>> # /usr/sbin/ntpdate -u -b
>>>> 28 Aug 11:21:35 ntpdate[10515]: no server suitable for synchronization
>>>> found
>>> Sure. That was what you asked for. It is unusual, but it is what you
>>> wanted. What is the problem?
>> If so, that means the clients can't update their time. I don't want
>> sync,
>> but I stilll need to provide the time service to clients. :-)
> Perhaps you are using the wrong tool for the job.  NTP is all about
> getting and keeping the CORRECT time.
> Your requirements seem sufficiently odd that you may need to write your
> own software!

Why should it he write his own software? NTP can do this very well.

If this is run in a closed network where it it sufficient that all nodes
just have the *same* time then this is absolutely OK.

For example, we have some customers who need to run their machines on TAI
rather than UTC. If they synchronize their top level NTP server to TAI then
using NTP to synchronize all the clients to TAI works like a charme.

Of course those folks must take care not to intermix NTP servers with UTC or
TAI or whatever, and they must not make those servers publicly accessible.

Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont

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