Use apt-get or yum to install the NTP daemon.
[root@server1 ~]# yum install ntp
Ensure the /etc/ntp.conf file contains 4 NTP servers. Instead of "distro" being listed, the name of the distribution should be listed, such as ubuntu, redhat, or centos. Your NTPd server will get time from these 4 NTP servers.
[root@server1 ~]# cat /etc/ntp.conf . . . server 0.distro.pool.ntp.org iburst server 1.distro.pool.ntp.org iburst server 2.distro.pool.ntp.org iburst server 3.distro.pool.ntp.org iburst . . .
To confiure your local NTP server to allow other computers in your network to use the machine as the NTP server, enter your network address and prefix.
The ps command can be used to determine if your system is using init or systemd. If PID 1 is init, then you will use the service command. If PID 1 is systemd, then you will use the systemctl command.
If your system is using systemd, use the systemctl command to start and enable ntpd.
systemctl enable ntpd systemctl start ntpd systemctl status ntpd
chkconfig ntpd on service ntpd start service ntpd status
Use the date command to verify the NTP server is getting the correct date and time from the NTP pool.
[root@server1 ~]# date Mon Jan 01 00:01:01 CDT 2016
Client PCs in your network can now be configured to use your NTP server.
NTP uses a term stratum to describe how far a device is from the reference clock.
Stratum can be 16 layers deep maximum.