/etc/ntp.conf The following configuration file defines various NTP servers to use with the primary server designated with the prefer tag. It also creates a drift file where ntpd stores the frequency offset. Since the documentation included with the package is sparse, visit the NTP website at for more information. server time-a.nist.gov prefer server time-b.nist.gov server tick.usno.navy.mil driftfile /var/cache/ntp.drift There are two options. Option one is to use run ntpd continuously and allow it to synchronize the time in a gradual manner. The other option is to run ntpd periodically (using cron) and update the time each time ntpd is scheduled. If you choose Option one, then create the bootscript /etc/rc.d/init.d/ntp and put the start and stop symlinks: cat > /etc/rc.d/init.d/ntp << "EOF" #!/bin/bash # Begin $rc_base/init.d/ntp source /etc/sysconfig/rc source $rc_functions case "$1" in start) echo "Starting ntpd..." loadproc ntpd ;; stop) echo "Stopping ntpd..." killproc ntpd ;; restart) $0 stop sleep 1 $0 start ;; status) statusproc ntpd ;; *) echo "Usage: $0 {start|stop|restart|status}" exit 1 ;; esac # End $rc_base/init.d/ntp EOF chmod 755 /etc/rc.d/init.d/ntp cd /etc/rc.d/init.d && ln -sf ../init.d/ntp ../rc0.d/K46ntp && ln -sf ../init.d/ntp ../rc1.d/K46ntp && ln -sf ../init.d/ntp ../rc2.d/K46ntp && ln -sf ../init.d/ntp ../rc3.d/S26ntp && ln -sf ../init.d/ntp ../rc4.d/S26ntp && ln -sf ../init.d/ntp ../rc5.d/S26ntp && ln -sf ../init.d/ntp ../rc6.d/K46ntp If you prefer to start ntpd periodically, add the following command to the root's crontab: ntpd -q