[ntp:questions] WARNING: someone's faking a leap second tonight

Terje Mathisen "terje.mathisen at tmsw.no" at ntp.org
Fri Aug 31 10:37:38 UTC 2012

Miroslav Lichvar wrote:
> On Thu, Aug 02, 2012 at 05:57:43AM +0000, Dave Hart wrote:
>> On Thu, Aug 2, 2012 at 1:17 AM, Chris Adams wrote:
>>> I'm still seeing leap=01 from (name1.glorb.com), a
>>> stratum-2 server in the US pool (a few of my systems have it in their
>>> list).
>> That particular system seems to have corrected its leap indication,
>> but plenty of other pool participants are advertising leap.  I have
>> this laptop set to associate with every IP in a list of all pool
>> servers as of late June.  The following are showing leap=01 now:
> [...]
>  From that list the following IPv4 servers still seem to be announcing
> a pending leap second:

I think I know one cause of those leap bits:

Two days ago I was asked to visit a local power company who had ntp 
problems, turned out that they had a bunch of routers acting as ntp 
relays, all with the leap bit set.

The cause was that they had a pair of Symmetricom 350's as their root 
servers, set up as mutual peers, and one of them did indeed claim that a 
leap second was upcoming.

I suspect this was caused by the combination of sticky leap bits and a 
possible race condition during the actual passing of the leap second on 
midnight UTC June 30.

Restarting the faulty ntpd process fixed the server issue but they still 
had to find time to restart all their distribution routers before 
midnight tonight.:-(

Symmetricom has not released any firmware updates for the 300 series 
since last fall.


- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"

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