Ubuntu – How to change the time server in ubuntu 12.04 LTS without installing the `ntp` package

ntp

I am on Ubuntu 12.04 LTS, in the dialog "Time and Date settings" there is a set of radio buttons labeled as "Set the time", the two options are "Manually" and "Automatically from the Internet":

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My current selection is "Automatically from the Internet" and I am fine with that apart from the fact that I would like to change the synchronization server (I would like to set it to ntp1.inrim.it). Is it possible without installing the ntp package? I did not find any way to change the server from the dialog.

Best Answer

There are two main ways to set the current time via NTP: ntpdate is a command-line tool that, when run, fetches the current time from an NTP server and sets the system time accordingly. ntpd is the NTP daemon which runs in the background and continuously adjusts the time slightly.

For servers, production environments and such, ntpd is better. However, for normal desktop PCs and end users, ntpdate is perfectly fine. In fact, when you install Ubuntu Desktop, it comes with ntpdate preinstalled, but not ntpd.

When you select "Automatically from the Internet" in your Ubuntu system settings as shown in your screenshot above, what happens is that at each boot Ubuntu will fetch the current time using ntpdate from ntp.ubuntu.com. If you want to change that server, you can edit the value of NTPSERVERS in /etc/default/ntpdate.

The alternative is to install ntpd (in package ntp), and configure that via /etc/ntp.conf. This is explained here in more detail:

https://help.ubuntu.com/lts/serverguide/NTP.html

However, if you do not want to install any additional packages and simply change the default server for ntpdate which comes pre-installed with Ubuntu, simply edit /etc/default/ntpdate.

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Ubuntu – Timezone appears to be set correctly, but time is 7 hours off

What am I missing?

Hello fellow Pacific Daylight Timer! :) Your system clock is defaulting to UTC (aka GMT), which is PDT+7.

Start the terminal with Ctrl-Alt-T, run sudo dpkg-reconfigure tzdata, and select the appropriate city in North America from the menu. Then exit. That should do it!

Ubuntu – How does Ubuntu synchronize time without ntp

This is done by synchronizing with ntpdate tool.

man ntpdate

NAME
       ntpdate - set the date and time via NTP

ntpdate sets the local date and time by polling the Network Time Proto‐
       col (NTP) server(s) given as the server arguments to determine the cor‐
       rect time. It must be run as root on the local host (unless the  option
       -q  is used). A number of samples are obtained from each of the servers
       specified and a subset of the NTP clock filter and selection algorithms
       are  applied  to  select  the best of these. Note that the accuracy and
       reliability of ntpdate depends on the number of servers, the number  of
       polls each time it is run and the interval between runs.

       ntpdate  can  be run manually as necessary to set the host clock, or it
       can be run from the host startup script to set the clock at boot  time.
       This is useful in some cases to set the clock initially before starting
       the NTP daemon ntpd. It is also possible to run  ntpdate  from  a  cron
       script.  However,  it  is important to note that ntpdate with contrived
       cron scripts is no substitute for the NTP daemon, which uses  sophisti‐
       cated  algorithms to maximize accuracy and reliability while minimizing
       resource use. Finally, since ntpdate does not discipline the host clock
       frequency as does ntpd, the accuracy using ntpdate is limited.

You can do so with

sudo ntpdate TIME-SERVER

TIME-SERVER lists can be founded here

Best Answer

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Ubuntu – Timezone appears to be set correctly, but time is 7 hours off

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