Ubuntu – How to configure NTP time synchronization on a server

ntpserver

I would like to configure my Ubuntu 12.04 server to synchronize its clock with a specific NTP server. Where to set this up?

Best Answer

Installation

or if you prefer command line ...

sudo apt-get install ntp

Configuration

sudo nano /etc/ntp.conf

This file will probably have the default Ubuntu server activated. You can check http://www.pool.ntp.org/zone/europe or http://www.pool.ntp.org/zone/north-america or http://www.pool.ntp.org/zone/asia for local (country based) servers. Just comment out all of the servers by adding a # in front of it and add in the one you want to use.

Activating the new changes

sudo service ntp restart

Checking if it synchs

sudo ntpq -c lpeer

This will show a list of all the servers and when they where last checked. Random example from the web:

enter image description here

See logging

sudo tail -f /var/log/syslog

Do make sure, if you are using a firewall, to open UDP 123.

Related Solutions

Ubuntu – How to set Ubuntu to synchronize the clock with a time server

It's generally recommended to run a service that uses NTP (Network Time Protocol) to regularly synchronize your computer's clock with a server. In recent versions of Ubuntu (at least since 18.10, or possibly earlier but I'm not sure), this is taken care of by the systemd-timesyncd service, which is installed and enabled by default, so there's no need to do anything special. If the service is available and active, running

timedatectl status

should tell you so.

For older versions of Ubuntu, you can follow instructions to set up an NTP daemon. There are several choices available but the "standard" one is in the package ntp. According to the instructions at the linked page,

sudo apt-get install ntp

will get everything set up to synchronize with Ubuntu's NTP server.

If you really do only want to synchronize the time once at startup and never again (until the next startup), see e.g. mfisch's answer. But again, this is not recommended and there's rarely any reason it would be beneficial.

Ubuntu – enable/disabling NTP server

Nowadays all the linux distributions after ubuntu14.04 use sysctemctl. So if you want to enable or disable ntp server use following.

sudo systemctl start ntp

sudo systemctl stop ntp

As a system administrator I prefer you to use the following technique:

sudo /etc/init.d/ntp restart

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Related Solutions

Ubuntu – How to set Ubuntu to synchronize the clock with a time server

Ubuntu – enable/disabling NTP server

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