[Dovecot] ntp revisited (so what to do ?)

[Lorens Kockum]

On Sun, May 08, 2011 at 06:45:01AM -0400, Jerry wrote:
> On Sun, 8 May 2011 11:07:04 +0100 (BST)
> Spyros Tsiolis <stsiol at yahoo.co.uk> articulated:
> 
> > So what you people say is :
> > 
> > 1. Run "ntpdate" during startup only once
> > 2. After that, keep time with ntpd
> 
> As I posted earlier using the technique I showed, on a FreeBSD system,
> there would be absolutely no reason to do so; however, I cannot vouch
> for that on other systems.

Right. As for running ntpdate, the years have passed and the debian manual now says:

       -g     Normally, ntpd exits with a message to the system log if the offset exceeds the panic threshold, which is  1000
              s by default.  This option allows the time to be set to any value without restriction; however, this can happen
              only once.  If the threshold is exceeded after that, ntpd will exit with a message to  the  system  log.   This
              option can be used with the -q and -x options.

       -q     Exit the ntpd just after the first time the clock is set.  This behavior mimics that of  the  ntpdate  program,
              which  is to be retired.

So, ntpdate is to be retired. In boot scripts either simply run

	ntpd -g

or, probably better:

	ntpd -gqx
	ntpd

In FreeBSD, AFAICS, setting

	ntpd_enable="YES"                    # Start time server
	ntpd_sync_on_start="YES"             # Synchronize on start

in /etc/rc.d corresponds to the second of the two, at least as
of FreeBSD 6.4, since before 6.4 the -x was apparently missing,
which would not correct big offsets, see:

http://lists.freebsd.org/pipermail/freebsd-bugs/2009-March/034439.html