Network Time Protocol (NTP) is crucial for synchronizing the clocks of computers over a network. Accurate timekeeping is essential for various applications, including logging events, security protocols, and data consistency. This article will guide you through configuring an NTP server on a Linux system, ensuring your network devices maintain accurate time.

Examples:

1. Installing NTP Package

   Before configuring the NTP server, you need to install the NTP package. Open a terminal and execute the following command:

   sudo apt-get update
   sudo apt-get install ntp

   For Red Hat-based distributions, use:

   sudo yum install ntp

2. Configuring NTP Server

   After installing the NTP package, you need to configure the NTP server. The main configuration file is located at /etc/ntp.conf. Open this file with your preferred text editor:

   sudo nano /etc/ntp.conf

   Add or modify the following lines to specify the NTP servers you want to synchronize with:

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

   The iburst option speeds up the initial synchronization.

3. Allowing NTP Service Through Firewall

   If you have a firewall enabled, you need to allow NTP traffic. For example, using ufw:

   sudo ufw allow 123/udp

   For firewalld:

   sudo firewall-cmd --permanent --add-service=ntp
   sudo firewall-cmd --reload

4. Starting and Enabling NTP Service

   Start the NTP service and enable it to start on boot:

   sudo systemctl start ntp
   sudo systemctl enable ntp

   For Red Hat-based distributions:

   sudo systemctl start ntpd
   sudo systemctl enable ntpd

5. Verifying NTP Synchronization

   To verify that your NTP server is synchronizing correctly, use the following command:

   ntpq -p

   This command will display a list of NTP servers and their synchronization status.