How to Configure NTP Server on CentOS 5.3

NTP (Network Time Protocol) installation and setup:

yum -y install ntp

Edit NTP config file: vi /etc/ntp.conf

At line 18, find "server 2.centos.pool.ntp.org" and add: server 0.north-america.pool.ntp.org server 1.north-america.pool.ntp.org server 2.north-america.pool.ntp.org server 3.north-america.pool.ntp.org server time.nrc.ca server time.chu.nrc.ca server tock.utoronto.ca server tick.utoronto.ca

Edit the other NTP config file: vi /etc/sysconfig/ntpd

At the second line of that file: OPTIONS="-u ntp:ntp -p /var/run/ntpd.pid"

Change the line to add the -x option to force a NTPD time sync at boot: OPTIONS="-x -u ntp:ntp -p /var/run/ntpd.pid"

Restart the NTPD service: service ntpd start

Ajust the system to automaticaly start this service at boot: chkconfig ntpd on