[CentOS] Strange NTP problem

Wed May 21 00:25:29 UTC 2008
Filipe Brandenburger <filbranden at gmail.com>

On Tue, May 20, 2008 at 3:46 PM, Alfred von Campe <alfred at von-campe.com> wrote:
> I have 30 identical Lenovo desktop systems running CentOS 5.1.  On one of
> those systems the clock is running slow (5+ minutes from yesterday to this
> morning and another minute since this morning) despite the fact that NTP is
> running on all of them and they all have the exact same /etc/ntp.conf file
> (I compared the MD5 sums of that file on all the systems).  Here is the
> output of "grep ntp /var/log messages" on the system with the problem since
> I restarted the NTP daemon earlier today:

Hi Alfred,

What is the output of "ntpq -np" ? You should have a line with a star
(*), otherwise it is not synchronizing. Start running NTP again, wait
for half an hour and issue that command to see what your output is. It
could be a problem related to filtering UDP traffic, either with
iptables on the machine itself, or some other router in the network
your machine is in.