[ntp:questions] NTPv4 Peer Event Codes - secret decoder ring sought

Dave Hart davehart at gmail.com
Thu Mar 18 15:23:27 UTC 2010


On Mar 18, 13:49 UTC, Joseph Gwinn <joegw... at comcast.net> wrote:
>  Dave Hart <daveh... at gmail.com> wrote:
> > If you want to be able to decode these bits for ntpd versions from
> > before and after the change correctly, you need to query the version
> > string of ntpd, sadly, such as with:
>
> > ntpq -c "rv 0 version"
>
> So that's how you get the NTP version (rather than the ntpq version)!
>
> When our sysadmins first installed NTPv4, they used the version command of ntpq,
> which said "4".  Check!  
>
> I came by a few days later to look at the purported NTPv4 loopstats and
> peerstats files, and (ever suspicious) checked to see what version of NTP had in
> fact generated them.  Still NTPv3.  The sysadmins had been snookered by ntpq,
> which failed to make unambiguous whose version it was reporting upon.  
>
> This had also happened to me back in the days of NTPv3, but I was saved because
> I knew that "4" could not be the answer.  But I never did figure out how to get
> ntpq to tell me the version of the ntp daemon.

C:\NTPb\bin>ntpq --version
ntpq - standard NTP query program - Ver. 4.2.7p20

C:\NTPb\bin>ntpq -c version
ntpq 4.2.7p20 at 1.2137-o Mar 18 15:04:17.18 (UTC-00:00) 2010  (4)

C:\NTPb\bin>ntpq -c "rv 0 version"
version="ntpd 4.2.7p20 at 1.2137-o Mar 14 8:23:33.64 (UTC-00:00) 2010
(9)"

C:\NTPb\bin>

The first two commands above are both reporting on the ntpq version,
in slightly different form.  The third reports on the local ntpd
version.  Tack on a hostname or IP address, and it'll tell you about a
remote ntpd version, if you're allowed to use ntpq with the server in
question.

> Is there available a written discussion of which changes were made and why?  
> This could be worth reading.

If there is, it would be in the archives of committers@, hackers@, or
questions at lists.ntp.org (all browsable via http://lists.ntp.org/) from
around May 13, 2008.  I was not active on the lists at that time.

> Looking at the code you suggested, I also see that the variable names are the
> same as in NTPv3 (and the names imply the original NTPv3 meanings), but the new
> NTPv4 comments on those variables seem to contradict the meanings implied by the
> names.  Not knowing the history makes it difficult to figure out just what is
> now meant.

I believe the 2008 changes were part of overall cleanup to bring the
reference implementation in-line with the draft NTP v4 specification.
The RFC form of that document has just been approved by the IESG and
should be a "proposed standard RFC" before too many more weeks.
Please refer to that document in your search for meaning:

ftp://ftp.rfc-editor.org/in-notes/internet-drafts/draft-ietf-ntp-ntpv4-proto-13.txt

Which is derived from the less ASCII-hamstrung:

http://www.eecis.udel.edu/~mills/database/reports/ntp4/ntp4.pdf

Cheers,
Dave Hart




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