Use apt-get or yum to install the NTP daemon on the client PC.

[root@client1 ~]# yum install ntp

In the /etc/ntp.conf file, comment out the 4 pool NTP pool servers, and then add peer ntp.example.com. Replace ntp1.example.com with the actual hostname of your NTP server. Peer configures the client to use the NTP server for time.

#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
peer ntp1.example.com

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 ensure ntpd is running.

systemctl status ntpd

If your system is using init, use the chkconfig and service commands to ensure ntpd is running.

service ntpd status

The ntpq -p command can be used to ensure the machine is using your NTP server. The record that begins with the * special character is the primary NTP server, and the records that begin with + are the backup NTP servers.

ntpq -p
. . .
     remote             refid      st t when poll reach   delay   offset  jitter
================================================================================
*ntp1.example.com  198.60.22.240    2 u   21   64    0    0.000    0.000   0.000
+ntp2.example.com  198.60.22.240    2 u   21   64    0    0.000    0.000   0.000

Use the date command to verify the machine is getting the correct date and time from the NTP server.

date
. . .
Mon Jan 01 00:01:01 CDT 2016