Cambiar la hora time date en fedora según la timezone

Instalar y configurar NTP en Linux CentOS para sincronizar el reloj del sistema

How do I install and configure NTP under CentOS Linux version 5.x or 6.x server to synchronize the system clock?

You can easily install NTP (Network Time Protocol, a means of transmitting time signals over a computer network) using the yum command under Red Hat or CentOS/Fedora Linux server or workstation based systems. You need to install the following packages:

1. ntp : ntpd server which continuously adjusts system time and utilities used to query and configure the ntpd daemon.
2. ntpdate : Utility to set the date and time via NTP.
3. ntp-doc : NTP documentation

Procedure: Setup NTPD on CentOS Linux

Open the terminal or login over the ssh session. You must login as as the root user. Type the following yum command to install ntp
# yum install ntp ntpdate ntp-doc

Turn on service, enter:
# chkconfig ntpd on

Synchronize the system clock with 0.pool.ntp.org server (use this command only once or as required):
# ntpdate pool.ntp.org

Start the NTP server. The following will continuously adjusts system time from upstream NTP server. No need to run ntpdate:
# /etc/init.d/ntpd start

o

# service ntpd start

Configure ntpd (optional)

Edit /etc/ntp.conf, enter:
# vi /etc/ntp.conf

Set public servers from the pool.ntp.org project:

server 0.rhel.pool.ntp.org
server 1.rhel.pool.ntp.org
server 2.rhel.pool.ntp.org

See this tutorial on how to configure NTPD for LAN based client on RHEL / CentOS Linux for more information.

Fuente: http://www.cyberciti.biz/faq/howto-install-ntp-to-synchronize-server-clock/