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Change Date, Time, and Time Zone in CentOS 8 - How to do it ?

This article covers how you can easily adjust the time, date, and time zone of your system in CentOS 8.

To change the time zone in Linux systems use the sudo timedatectl set-timezone command followed by the long name of the time zone you want to set.


How to Synchronize Time on Installed Linux Operating Systems ?

1. On the Linux machine, log in as root.

2. Run the ntpdate -u <ntpserver> command to update the machine clock. For example, ntpdate -u ntp-time.

3. Open the /etc/ntp. conf file and add the NTP servers used in your environment.

4. Run the service ntpd start command to start the NTP service and implement you configuration changes.


Importance of man command in Linux:

man command in Linux is used to display the user manual of any command that we can run on the terminal. 

It provides a detailed view of the command which includes NAME, SYNOPSIS, DESCRIPTION, OPTIONS, EXIT STATUS, RETURN VALUES, ERRORS, FILES, VERSIONS, EXAMPLES, AUTHORS.


Install Chrony on Linux Mint - Easy steps to do it ?

This article covers how to #install Chrony on Linux Mint 20. Once it will be installed on your system, its daemon will silently work in the background to synchronize your system's clock with the #NTP server. 

However, if you do not want Chrony to perform this job any longer, then you can simply uninstall it as well.

Chrony is a flexible implementation of the Network Time Protocol (NTP). 

It is used to synchronize the system clock from different NTP servers, reference clocks or via manual input.


Chrony comes with two programs:

1. chronyc – command line interface for chrony

2. chronyd – daemon that can be started at boot time


How to Install #Chrony in #Linux :

On some systems, chrony may be installed by default. Still if the package is missing, you can easily install it. 


You can install chrony Using your default package manager tool on your respective Linux distributions using following command:

# yum -y install chrony    [On CentOS/RHEL]

# apt install chrony       [On Debian/Ubuntu]

# dnf -y install chrony    [On Fedora 22+]


To check the status of chronyd use the following command:

# systemctl status chronyd      [On SystemD]

# /etc/init.d/chronyd status    [On Init]


If you want to enable chrony daemon upon boot, you can use the following command:

# systemctl enable chronyd       [On SystemD]

# chkconfig --add chronyd        [On Init]


How to Check Chrony Synchronization in Linux ?

To check if chrony is actually synchronized, we will use it's command line program chronyc, which has the tracking option which will provide relevant information:

# chronyc tracking


To check information about chrony’s sources, you can issue the following command:

# chronyc sources


Process to configure an NTP server and client on Ubuntu 20.04 LTS ?

This article will guide you on how to configure the NTP server on the #Ubuntu machine and then sync a clock of NTP client machine. Now you can easily set up NTP server and connect multiple client machines with it for time synchronization.

The Network Time Protocol (NTP) is a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks.

NTP is intended to synchronize all participating computers to within a few milliseconds of Coordinated Universal Time (UTC).


How do I start #NTP on Linux?

In order to add command line options to the ntpd service (/etc/init. d/ntpd), one has to edit /etc/sysconfig/ntpd file and add the desired option to the OPTIONS variable, and restart the service via 'service ntpd restart'.


What port does NTP use?

NTP time servers work within the TCP/IP suite and rely on User Datagram Protocol (UDP) port 123. NTP servers are normally dedicated NTP devices that use a single time reference to which they can synchronize a network. 

This time reference is most often a Coordinated Universal Time (UTC) source.


To Sync NTP client with server via command line:

1. Edit the /etc/ntp.

2. Search for the lines beginning server .

3. Replace the server entries with the IP address or hostname of the NTP server or servers with which you want to synchronize.

4. Save the file.

5. Configure the NTP client service to start at run level 3 when the appliance boots.


NTP Server and Client on Ubuntu - How to Configure it ?

This article will guide you on how to configure the #NTP server on Ubuntu. You will learn how to configure the NTP client on another #Ubuntu machine and synchronize it with the NTP server. By means of this, you can easily synchronize all system clocks in a network.

The Network Time Protocol (NTP) is a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks.

NTP is intended to synchronize all participating computers to within a few milliseconds of Coordinated Universal Time (UTC).


To Configure NTP server:

1. Install NTP Server. First, install NTP package on your server using the appropriate package management tool that is available on your Linux distro.

2. Setup Restrict values in ntp. conf.

3. Allow Only Specific Clients.

4. Add Local Clock as Backup.

5. Setup NTP Log Parameters.

6. Start the NTP Serrver.


To Configure NTP client:

1. To configure your Linux system as an NTP client, you will need to install the ntp daemon (ntpd).

2. The ntpd configuration file is located at /etc/ntp.conf.

3. This file contains the list of NTP servers that will be used for time synchronization.

4. Next, restart the NTP deamon with the sudo service ntp reload command