How to configure the NTP Daemon to keep a RHEL 7-based server's time accurate

Introduction

This article provides the steps to configure the NTP daemon to keep a RHEL 7-based server's time accurate.

Procedure

1. Access the server's command line as the 'root' user via SSH or "Terminal" in WHM.
2. Stop and disable the cronyd service.

   systemctl stop chronyd; systemctl disable chronyd

3. Install the ntp package.

   yum install ntp -y

4. Enable the ntpd service.

   systemctl enable ntpd

5. Open outbound UDP port 123 in all applicable firewall and security services.
6. Open the /etc/ntp.conf file in your preferred text editor.
7. Comment out the existing server lines.

   #server 0.centos.pool.ntp.org iburst
   #server 1.centos.pool.ntp.org iburst
   #server 2.centos.pool.ntp.org iburst
   #server 3.centos.pool.ntp.org iburst

8. Add a new server line for the hostname of the NTP server to query.

   server time.google.com

9. Save the changes and exit the text editor.
10. Start the ntpd service.

    systemctl start ntpd

Additional resources

Chapter 19. Configuring NTP Using ntpd: 19.17. Configure NTP