How to install and Configure NTP client on CentOS/RHEL to Synchronize the Clock

NTP, Network Time Protocol, it is an Internet protocol used to synchronize the clocks of computers or servers to some NTP server on internet or intranet. In CentOS, it is very easy to install and configure the ntp client.

Install your NTP client using yum command:

[root@server ~]# yum install ntp
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * addons:
 * base:
 * epel:
 * extras:
 * updates:
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package ntp.x86_64 0:4.2.2p1-9.el5.centos.2.1 set to be updated
--> Finished Dependency Resolution

Dependencies Resolved

 Package      Arch            Version                            Repository     Size
 ntp          x86_64          4.2.2p1-9.el5.centos.2.1           base          1.3 M

Transaction Summary
Install       1 Package(s)
Upgrade       0 Package(s)

Total download size: 1.3 M
Is this ok [y/N]: y
Downloading Packages:
ntp-4.2.2p1-9.el5.centos.2.1.x86_64.rpm                       | 1.3 MB     00:04
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing     : ntp                                                           1/1

  ntp.x86_64 0:4.2.2p1-9.el5.centos.2.1


Configure your ntp.conf file and pointing to your NTP server

[root@server ~]# vi /etc/ntp.conf
server     //set this to your primary NTP server  - Line 17
server     //set this to your Secondary NTP server (Optional)  - Line 18
server     //set this to your tertiary  NTP server(Optional)  - Line 19

As for example :

server ntp1.server.local
server ntp2.server.local

Restart your ntp client using below command:

[root@server ~]# service ntpd restart


[root@server ~]# /etc/init.d/ntpd restart

Test your ntp client status whether properly configured or not by running below command:

[root@server ~]# ntpq -p