Configurar Hora RHEL

http://www.fir3net.com/Redhat-/-Fedora/how-to-set-the-time-date-and-timezone-in-centos.html
http://serverfault.com/questions/368602/how-do-i-update-a-centos-servers-time-from-an-authoritative-time-server


MANUALMENTE:

rm /etc/localtime
ln -s /usr/share/zoneinfo/GMT /etc/localtime
date 072522172010
hwclock --systohc


[root@Fileserver ~]# date
Sun Jul 25 22:38:47 GMT 2010
[root@Fileserver ~]# hwclock
Sun 25 Jul 2010 10:38:51 PM GMT  -0.125883 seconds

Instalar NTP

yum install ntp
chkconfig ntpd on
ntpdate pool.ntp.org
service ntpd start

# sync hw clock 

hwclock --systohc
#test
date 

resumen en una linea
date && yum -y install ntp && chkconfig ntpd on && ntpdate pool.ntp.org && service ntpd start && hwclock --systohc && date