Proper Method of Time Sync?

Dan Nelson dnelson at
Fri Apr 14 15:54:01 UTC 2006

In the last episode (Apr 14), Jonathan Horne said:
> i have read about 2 methods to sync the time on a freebsd box.
> 1) add these entries to /etc/rc.conf:
> ntpdate_enable="YES"
> ntpdate_flags=""
> ... and let the system do a one-time sync at bootup, and rely on this
> single method for timesync.
> 2) add this entry to /etc/rc.conf
> ntpd_enable="YES"
> add the file with these contents to /etc/rc.conf:
> server
> driftfile /var/db/ntp.drift
> restrict mask nomodify notrap
> so, i have a workstation and a server, which i originally did method
> 1 on, but soon enough, time drifted quite a bit.  so i switched it to
> the 2nd method, and they appear to be sync'd perfectly.  a third box
> i set up, i did only method 2, and this one did not stay synced at
> all.  after i manually ran 'ntpdate -v -b', this box
> straightend up.
> are both methods required for proper time syncronization, or can one
> rely only on the ntpd method?

ntpd takes a while to sync up and by default won't adjust the clock if
it's more than 1000 seconds off, so it's a good idea to enable ntpdate
as well.  You don't need the ntpdate_flags variable; the startup script
will grab server names out of /etc/ntp.conf .

	Dan Nelson
	dnelson at

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