Install and Configure NTP Server and Client on AlmaLinux 9

In this guide, we want to teach you How To Install and Configure NTP Server and Client on AlmaLinux 9.

A ‘network time server’ is a general description of the software on the NTP- Network Time Protocol server which is running on any server/computer platform. It is applied to the network appliance (tray mount, rack, etc), which acquires and uses time from an external source to maintain time within its local internal clock, and then supplies the time to its connected network. This is achieved using the NTP or Network Time Protocol.

Steps To Install and Configure NTP Server and Client on AlmaLinux 9

To complete this guide, you must log in to your server as a non-root user and set up a basic firewall. To do this, you can follow our guide on Initial Server Setup with AlmaLinux 9.

Installing Chrony on AlmaLinux 9

To install NTP on your server, you need to have Chrony installed on your server.

Chrony is an implementation of the Network Time Protocol and is useful in a number of ways.

First of all, check the current time zone of your server with the following timedatectl command:

timedatectl

Example output:

Output
Time zone: America/New_York (EDT, -0400)

Next, update your local package index with the following command:

sudo dnf update -y

Then, install Chrony on AlmaLinux 9 with the following command:

sudo dnf install chrony -y

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 p>
     Active: active (running) since Mon 2022-09-26 05:07:23 EDT; 8min ago
       Docs: man:chronyd(8)
             man:chrony.conf(5)
   Main PID: 562 (chronyd)
      Tasks: 1 (limit: 23609)
     Memory: 2.2M
        CPU: 66ms
     CGroup: /system.slice/chronyd.service
             └─562 /usr/sbin/chronyd -F 2
...

Configuring NTP Server on AlmaLinux 9

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 the 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

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
===============================================================================
^? connected.by.freedominte>     2   6     1     8  +1183us[+1183us] +/-   25ms
^? time.richiemcintosh.com       2   6     1     8  +1575us[+1575us] +/-   83ms
^? washington.homemail.org       2   6     1    10    +15ms[  +15ms] +/-   95ms
^? clock.isc.org                 3   6     1    11  +4859us[+4859us] +/-  152ms

At this point, you need to allow NTP service through the AlmaLinux 9 firewall:

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

Reload the firewall to apply the changes:

sudo firewall-cmd --reload

Configuring NTP Client on AlmaLinux 9

At this point, you need to install the NTP client on a client machine and configure it with the Chrony.

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 AlmaLinux 9 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 - -

That’s it, you are done.

Conclusion

At this point, you have learned to Install and Configure NTP Server and Client on AlmaLinux 9.

Hope you enjoy it.

For more guides and articles, you can visit the Orcacore website.