Install ntp
$ yum install ntp
Turn on service on startup
$ chkconfig ntpd on
Synchronize the system clock with ntp server:
go to http://www.pool.ntp.org/fr/ to find the right zone
$ ntpdate pool.ntp.org
Start the NTP service:
$ /etc/init.d/ntpd start
Check synchronization :
$ ntpq -p