The centos 4.x we are using as platform for the VMWare VMs (yes, I know there is version 5, but we need to be compliant with RHEL 4.x because of the ATG requirements) installs by default the NTP client.

Here is sequence of steps that needs to be performed to enable automatic synchronization of the clocks.

1) make sure the DNS works

cat /etc/resolv.conf
sudo vi /etc/resolv.conf

and check that nameservers point to something meaningfull, e.g:


2) check that you have ntpd installed

cat /etc/ntp.conf

- inspect the content of the file, it is quite well documented

3) make it work in runlevels 2345

/sbin/chkconfig --list | grep ntpd

- this will most likely show "off" for all runlevels

sudo /sbin/chkconfig --level 2345 ntpd on

4) Initial sync

sudo /usr/sbin/ntpdate

- do this twice, on second you should get very small difference

5) Start service / restart service

sudo /sbin/service ntpd start

Making this a blog post so that next time I need to do it I can easily find it :-). Maybe somebody else will find it useful as well.