In this guide, we want to teach you to Set up and Configure NTP Server and Client on Rocky Linux 8.
Network Time Protocol (NTP) is a set of rules and conventions for synchronizing server clocks in a computer network. A client can request time information from an NTP server over a packet network.
NTP is a cost-effective and reliable method of delivering time information accurately within a few milliseconds of Coordinated Universal Time (UTC) that has been widely used in networks across the globe since the 1980s.
Set up and Configure NTP Server and Client on Rocky Linux 8
To set up NTP on your server, you need to log in as a non-root user with sudo privileges and set up a basic firewall. To do this, you can check our guide the Initial Server Setup with Rocky Linux 8.
Follow the steps below to complete this guide.
Install Chrony on Rocky Linux 8
You need to have Chrony installed on your server for installing NTP on Rocky Linux 8.
Chrony is a flexible Network Time Protocol implementation (NTP). It can sync the system clock with NTP servers, reference clocks (such as a GPS receiver), and manual input via wristwatch and keyboard.
Check Current time Zone on Rocky Linux
First of all, you need to check the current time zone of your server with the following command:
timedatectl
Example output:
Output
Time zone: America/New_York (EDT, -0400)
Then, update your local package index with the command below:
sudo dnf update -y
Install Chrony
Then, install Chrony on Rocky Linux 8 with the following command:
sudo dnf install chrony -y
Manage Chrony Service
Start and enable your Chrony service with the commands below:
# sudo systemctl start chronyd # sudo systemctl enable chronyd
To verify that your Chrony service is active and running on your server, run the command below:
sudo systemctl status chronyd
Output chronyd.service - NTP client/server Loaded: loaded (/usr/lib/systemd/system/chronyd.service; enabled; vendor pre> Active: active (running) since Mon 2022-04-11 06:59:56 EDT; 10min ago Docs: man:chronyd(8) man:chrony.conf(5) Main PID: 23975 (chronyd) Tasks: 1 (limit: 11409) Memory: 1.6M CGroup: /system.slice/chronyd.service └─23975 /usr/sbin/chronyd
Now that you have NTP installed on your server, you need to make some configuration changes.
Configure NTP Server on Rocky Linux 8
The default configuration file for the NTP server is /etc/chrony.conf
.
First, you need to open the file with your favorite text editor, here we use vi:
sudo vi /etc/chrony.conf
At the file, comment on the Pool line by adding the # from the beginning of the line.
Add a list of NTP servers close to your location. In my case is US, you can use this link:
#pool 2.cloudlinux.pool.ntp.org iburst server 0.us.pool.ntp.org server 1.us.pool.ntp.org server 2.us.pool.ntp.org server 3.us.pool.ntp.org
Allow NTP Client Access
Also, you need to Allow NTP client access from the local network. To do this, edit the line below:
# Allow NTP client access from local network.
allow 192.168.201.0/24
When you are done, save and close the file.
In the next step, you need to set NTP synchronization with the following command:
sudo timedatectl set-ntp true
Restart your Chrony service to apply the changes:
sudo systemctl restart chronyd
Now you can check whether your NTP server is working or not with the following command:
chronyc sources
Output
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
^? ntp.xtom.com 2 6 1 4 +592us[ +592us] +/- 139ms
^? mail.fotiu.com 3 6 1 4 -15ms[ -15ms] +/- 140ms
^? 2605:6400:d814::ad18 2 6 1 4 -2515us[-2515us] +/- 111ms
^? ns1.backplanedns.org 2 6 1 7 +7127us[+7127us] +/- 140ms
Configure Firewall
At this point, you need to allow NTP service through the Rocky Linux 8 firewall:
sudo firewall-cmd --permanent --add-service=ntp --permanent
Reload the firewall to apply the changes:
sudo firewall-cmd --reload
Now that you have configured NTP on your server, you need to configure the NTP client.
Configure NTP Client on Rocky Linux 8
At this point, you need to install the NTP client on a client machine and configure it with the Chrony. Here our client machine is Rocky Linux.
First, you need to set the correct timezone on your client machine:
sudo timedatectl set-timezone America/New_York
Then, install Chrony on your client machine:
sudo dnf install chrony -y
Edit the configuration file /etc/chrony.conf and point to your NTP server.
sudo vi /etc/chrony.conf
#pool 2.fedora.pool.ntp.org iburst
server your-server-ip-address
When you are done, save and close the file.
Restart your Chrony service to apply the changes:
sudo systemctl restart chronyd
Next, set NTP synchronization:
sudo timedatectl set-ntp true
Enable your Chrony service to start on boot:
sudo systemctl enable chronyd
Now verify your time synchronization:
chronyc sources
Output MS Name/IP address Stratum Poll Reach LastRx Last sample =============================================================================== ^* server-ip-address 4 6 37 29 +14us[ +30us] +/- 11ms
Finally, you can check on NTP clients. To do this, log in to your Rocky Linux 8 server and run the command below:
sudo chronyc clients
Output Hostname NTP Drop Int IntL Last Cmd Drop Int Last =============================================================================== localhost 0 0 - - - 5 0 10 13 client-machine-ip 19 0 6 - 67 0 0 - -
For more information, you can visit the NTP Documentation page.
Conclusion
At this point, you learn to Set up and Configure NTP Server and Client on Rocky Linux 8.
Hope you enjoy it.
You may be like these articles:
Install and Configure NTP Server and Client on AlmaLinux 9
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