On 12/02/15 12:53, David chen wrote: > but why the second line timestamp(13:59:59) is less than the first line's(14:00:01)? Total guess here, but I suspect what's happening is that the ntp server on your LAN that this client is getting the time from in the hardcoded 'ntpdate' command is about ~1 second out from the servers the client is using from /etc/ntp.conf Further complicating matters is the output from the hardcoded 'ntpdate' command doesn't appear in /var/log/messages until it's completed thus giving the output of 'ntpdate' all at once. Add these two together, and you get a TARDIS :D Cheers, Pete.