[ntp:questions] How to insert a leap second with ntpq

Dave Hart davehart at gmail.com
Thu Jun 21 06:24:41 UTC 2012

On Thu, Jun 21, 2012 at 4:01 AM, ZHOU.Jun <dimotion.zhou at gmail.com> wrote:
> 在 2012年6月20日星期三UTC+8下午9时00分31秒,ZHOU.Jun写道:
>> 在 2012年6月20日星期三UTC+8下午1时42分04秒,Dave Hart写道:
>> > On Wed, Jun 20, 2012 at 4:30 AM, ZHOU.Jun wrote:
>> > > I need to do some tests with ntpd and I want to have NTP packets set Leap
>> > > indicator in order to insert a leap second to a Linux server running ntp client.
>> > >
>> > > How can I configure the server to generate a packet with Leap indicator 0x01?
>> >
>> > Install the "leapfile" informing ntpd of the leap second to be
>> > inserted at the end of this month:
>> >
>> > http://support.ntp.org/bin/view/Support/ConfiguringNTP#Section_6.14.
>> >
>> > Set the clock to the last day of this month -- verify with "date -u"
>> > which will show the UTC time.  The insertion happens at the start of
>> > July 1 UTC.
>> >
>> > Cheers,
>> > Dave Hart
>> Hi Hart
>> Thanks for your information.
>> I will follow your method.
> Hello Hart,
> I found that my ntp version is 3-5.93e which is before 4.2.6
> So I should use the method 6.14.2. NTP Versions before 4.2.6 right?
> If I am right, then from the description, I think I need to copy this leap second file to crypto directory. So could you tell me where is the crypto directory?
> Thanks in advance.
> The leap second file must be copied to the crypto directory configured for ntpd, and inside that directory a link must be created which points to that file. The standard name for the link is ntpkey_leap. However, this can be overridden by a configuration parameter.

This won't work for you -- your version is too old to have the
autokey-based leap second file support -- so there is no way to use a
leapfile with 3-5.93e.


suggests you can set the leapwarning variable to 01 (or 1, presumably)
to warn of an insertion at the end of the current day.  I suspect that
requires an authenticated ntpdc operation, but I really don't know.
You'll have to experiment, or use a newer version of ntpd.

Dave Hart

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