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

Jeffrey Lerman jeffrey.lerman at gmail.com
Sat Aug 4 00:22:05 UTC 2012

Fair enough.  Though with a definition like that, it's formally 
impossible to distinguish bugs from intentional behavior ("features").

Anyway, I'm guessing you know the design intent, as well as the relevant 
implementations, pertaining to the question I posed further down in that 
email, namely:

Is the leap bit supposed to be cleared by a client if it gets LI=00 from 
a server?  Or is the bit only *set* based on information from a server, 
and cleared only upon application of the leap second?  If the latter is 
the current implementation, it might well explain the bogus leap second 
behavior many of us saw a few days ago.  Unless you have a different 


On 8/3/2012 5:08 PM, Harlan Stenn wrote:
> Jeff wrote:
>> Oh, my mistake:  I quote RFC5905 below, which is for NTPv4, which is
>> technically in _draft_ status - though it does seem pretty far along and
>> I believe current ntpd adheres to NTPv4, not v3.
> The NTP code *defines* the spec, and there will be times when the
> current spec and the code match, and there are times when the current
> code is getting ready to define the *next* spec.
>> For what it's worth the most recently approved protocol is, technically,
>> NTPv3, documented in RFC1305 - and that one does say "current day" -
>> though again, ntpd respects the end-of-month rule.
> That depends on your definition of "Approved".  NTPv3 (RFC 1305) never
> made it out of DRAFT status.
> RFC 5905 is a "Proposed Standard".
> H

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