[ntp:questions] Re: ntpdate functions successors

Harlan Stenn stenn at maccarony.ntp.org
Mon Oct 11 08:37:44 UTC 2004


>>>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?

I believe that in this mode the daemon will not be in sync, so it will not
server time.

>>>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".

If the time is "close" it will slew (and that adjustment should happen
in well under a second).  If the time is not close it will be stepped.

You can use the tinker variables to adjust this behavior.

The -g is primarily used to avoid the "sanity" check and update the
clock even if the time is off by more than 1000 seconds.

>>>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.

I thought Dave had a solution to this problem in a previous message.

And -l stdout should make for easier parsing.

>>>All listed applications are widely used in our network and it's strongly
>>>interesting what we shall do when the main useful tool disappear.

ntpdate has a number of significant bugs.

>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.

I really don't understand what you are saying.  What we describe does not
turn hosts into time servers.

H



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