NTP stands for Network Time Protocol. It is a protocol or service which is used to synchronize the clock of your client machines with the clock of a server. The clock of the server is further synced to the Internet.
In this article, I am going to show how you can set up an NTP server in your environment and sync the clock with the client machines. I have executed all the commands and procedures on my Debian 10 machines.
Update Debian package repository
Open up the terminal with root privileges and run the following command to update the package repository.
apt-get update
Below is the sample output.
Install NTP server on Debian
To install an NTP server, run the following command on the terminal. When you are prompted, enter Y from the keyboard.
apt-get install ntp
Wait for the installation to finish. This may take several minutes to complete depending on your Internet speed.
Below is the sample output.
Verifying an installation
You can verify the installation and version by executing the below command.
sntp --version
Restart the NTP server
Run the following command to restart the NTP server.
systemctl restart ntp
To verify whether the NTP service is actually running, execute the following command.
systemctl status ntp
Below is the sample output which shows that the NTP service is running on the server.
Configure the firewall on NTP server so that clients can access it
Open up the terminal on the NTP server and run the following command with root privileges.
iptables -A OUTPUT -p udp --dport 123 -j ACCEPT
iptables -A INPUT -p udp --sport 123 -j ACCEPT
Below is the sample output.
Installing an NTP client
Let us configure the NTP client to be time synced with the NTP server. For this, you have to install the ntpd daemon on the client machine.
apt-get install ntpdate
Wait for the installation to finish. This could take several minutes to complete depending on your internet speed.
Below is the sample output.
Installing an NTP on the client
Open up the terminal with root privileges and run the following command.
apt-get install ntp
Wait for the installation to finish. This may take several minutes to complete depending on the internet speed.
Below is the sample output.
Configuring the NTP client
Once you have installed the NTP daemon on the client machine, it is now time to configure it so that its clock can be synced with the NTP server.
Run the following command to open a configuration file in the nano editor.
nano /etc/ntp.conf
Add the following lines,
server 10.1.1.1 prefer iburst
Below is the sample output after adding the above line in the configuration file.
Restart the NTP service after adding the above line by running the following command on the terminal with root privileges.
systemctl restart ntp
To check the status, run the following command on the terminal.
ntpq -p
Below is the sample output.
Conclusion
We are done with the basic configuring of an NTP server and client. Good luck!
