If your clock is wrong you might have a wrong hwclock set…
yum install ntp ntpdate -s it.pool.ntp.org hwclock -w |
on a side note to change the timezone on RHEL 6.x adjust the clock settings config file:
nano -w /etc/sysconfig/clock |
set it as you wish:
ZONE="Europe/Rome" |
then set the localtime
cp /usr/share/zoneinfo/Europe/Rome /etc/localtime |