[ntp:questions] Re: ntpdate functions successors

Valentin Nechayev netch at segfault.kiev.ua
Sat Oct 9 19:46:30 UTC 2004

>>> Harlan Stenn wrote: 

HS> Most everything you ask for can be done, and it is described in the
HS> html pages.

But not in some aspects, so I'll ask more.

>>1. Providing synchronized time on a host without having ntpd listening
>>(to exclude any possibility of being abused or exploited), typical to
>>unix workstations.
>>(ntpdate in crontab)
HS> ntpd -q

Does it mean ntpd really ignores any packets expect replies to its requests?
Or one should write a bunch of explicit restrictions?

>>2. Always use time stepping on system startup, regardless of offset value.
>>(ntpdate -b)
HS> ntpd -g
No. At least manpage says nothing for the question whether it would do
_stepping_ or _adjusting_. It only says "any offset is valid".

>>3. Use time stepping when local timer lags behind, and time adjusting when
>>local timer outflies. (Now it may be implemented using simple shell script
>>around ntpdate; second call with -b or -B.)
HS> ntpd -x is pretty close to the -b/-B stuff.

>>4. Checking working of remote server and its offset, with output suitable
>>for machine parsing (in scripts) and without affecting current daemon.
>>(ntpdate -uq)
HS> Not sure how to do this either.
Well, it's still required for diagnostics.

>>All listed applications are widely used in our network and it's strongly
>>interesting what we shall do when the main useful tool disappear.
HS> ntpdate has many limitations and problems that are addressed by using
HS> ntpd instead.
ntpd was oriented to be _server_ program for too long time. I see no
need to change any host to be server, it's contrary to common tendence
which leads to provide maximal closeness.

HS> Dave, can we think of a way to say "it's OK to step forward, but always slew
HS> backwards"?

HS> Also, I wonder if we could use:
HS>  tinker panic -0
HS> to mean "just abort and report what the time difference is" (or something
HS> similar).

And will it be easily parseable (at least as with current ntpdate)?


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