ubuntu

Using TeamViewer tar package on Ubuntu

 in GNU/Linux  tagged teamviewer / ubuntu by

Recently, we needed to start TeamViewer on an Ubuntu GNU/Linux machine where we did not want to install it.
To do so, we used the 64bit tar package from the TeamViewer Linux download page.

After downloading the package and extracting its content, we realised that we could not start TeamViewer (./teamviewer) as is.
In order to troubleshoot, we used a terminal and executed the check libraries functionality (./tv-setup checklibs;) from the archive folder that gave us some missing dependencies:

./tv-setup checklibs

    -=-   TeamViewer tar.xz check   -=-     

  In order to use the tar.xz version of TeamViewer,
  you have to make sure that the necessary libraries are installed.

    Writing raw output to /home/xeirwn/Downloads/teamviewer_13.1.3026_amd64/teamviewer/logfiles/DependencyCheck.log

 Analyzing dependencies ...           
    libQt5Core.so.5 => not found
    libQt5DBus.so.5 => not found
    libQt5Gui.so.5 => not found
    libQt5Network.so.5 => not found
    libQt5Qml.so.5 => not found
    libQt5Quick.so.5 => not found
    libQt5WebKit.so.5 => not found
    libQt5WebKitWidgets.so.5 => not found
    libQt5Widgets.so.5 => not found
    libQt5X11Extras.so.5 => not found

    The libraries listed above seem to be missing.
    Please find and install the corresponding packages.
    Then, run this command again.

    QtQuickControls seems to be missing

    The following command may be helpful:
      apt-get install libdbus-1-3 libqt5gui5 libqt5widgets5 libqt5qml5 libqt5quick5 libqt5webkit5 libqt5x11extras5 qml-module-qtquick2 qml-module-qtquick-controls qml-module-qtquick-dialogs qml-module-qtquick-window2 qml-module-qtquick-layouts;

Solution: Following the instructions we executed the following:

sudo apt-get install libdbus-1-3 libqt5gui5 libqt5widgets5 libqt5qml5 libqt5quick5 libqt5webkit5 libqt5x11extras5 qml-module-qtquick2 qml-module-qtquick-controls qml-module-qtquick-dialogs qml-module-qtquick-window2 qml-module-qtquick-layouts;

After the installation of the libraries, we executed once more the check libraries functionality (./tv-setup checklibs;)  where we got the message that everything seem to be OK.

 ./tv-setup checklibs

    -=-   TeamViewer tar.xz check   -=-     

  In order to use the tar.xz version of TeamViewer,
  you have to make sure that the necessary libraries are installed.

    Writing raw output to /home/xeirwn/Downloads/teamviewer_13.1.3026_amd64/teamviewer/logfiles/DependencyCheck.log

 Analyzing dependencies ...           

    All library dependencies (*.so) seem to be satisfied!

    QtQuickControls seems to be installed

Trying to start the (./teamviewer)  application did not gave an error but it would not start again.
It appeared that there was a service running which would not allow the GUI to show up.
To avoid too much fuss, we restarted the machine and tried (./teamviewer)  once more, this time with success.
So after installing the libraries and restarting the machine, we were able to start TeamViewer on our Ubuntu machine without installing it.

Ubuntu: install / start/stop enable/disable ssh server 2

 in GNU/Linux  tagged disable / enable / install / openssh / openssh-server / server / ssh / SSH server / start / status / stop / systemctl / ubuntu by

OpenSSH is a freely available version of the Secure Shell (SSH) protocol family of tools for remotely controlling, or transferring files between, computers.

Install SSH server

To install the openssh-server on an Ubuntu, you need execute the following command as root or using sudo:

apt-get install openssh-server -y;

Disable SSH server

To disable the ssh service, execute the following command as root or using sudo:

systemctl disable ssh;

Enable SSH server

To enable the ssh service, execute the following command as root or using sudo:

systemctl enable ssh;

Stop SSH server

To stop (or deactivate) the ssh service, execute the following command as root or using sudo:

systemctl stop ssh;

Start SSH server

To start (or activate) the ssh service, execute the following command as root or using sudo:

systemctl start ssh;

Status of SSH server

To check the status of the ssh service, execute the following command as root or using sudo:

systemctl status ssh;

CONCEPTS

In a nutshell:

  • enabled is a service that is configured to start when the system boots
  • disabled is a service that is configured to not start when the system boots
  • active is a service that is currently running
  • inactive is a service that is currently stopped and may be disabled, but it can be started and become active

In much more detail:

systemd provides a dependency system between various entities called “units” of 12 different types. Units encapsulate various objects that are relevant for system boot-up and maintenance. The majority of units are configured in unit configuration files, whose syntax and basic set of options is described in systemd.unit(5), however some are created automatically from other configuration, dynamically from system state or programmatically at runtime. Units may be “active” (meaning started, bound, plugged in, …, depending on the unit type, see below), or “inactive” (meaning stopped, unbound, unplugged, …), as well as in the process of being activated or deactivated, i.e. between the two states (these states are called “activating”, “deactivating”). A special “failed” state is available as well, which is very similar to “inactive” and is entered when the service failed in some way (process returned error code on exit, or crashed, or an operation timed out). If this state is entered, the cause will be logged, for later reference. Note that the various unit types may have a number of additional substates, which are mapped to the five generalized unit states described here.
— From man systemd

 

Ubuntu SSHD listen to multiple ports

 in GNU/Linux  tagged cloudflare / mulitple ports / server / ssh / sshd / sshd_config / ubuntu by

Recently, we’ve setup an Ubuntu server behind CloudFlare that needed to listen for SSH connections.
Unfortunately, CloudFlare does not allow connections to the default SSH port which is 22.
So, to achieve what it was needed we either had to change the port that the SSH service was listening to or add an additional port.
We decided to go with the option of listening to multiple ports for SSH connections, this way users that were also behind the CloudFlare CDN could still continue to use their SSH clients without being forced to define the connection port manually.

The port listening setting is available in /etc/ssh/sshd_config, using sudo we edited the file with a text editor and searched for the following lines:

# What ports, IPs and protocols we listen for
Port 22

Right after the line that contains Port 22, we added another line for the new port (to see the list of all available open ports on CloudFlare, check this post)

And the file became as follows:

# What ports, IPs and protocols we listen for
Port 22
Port 2053

Afterwards, we restarted the SSHD service to apply the changes by executing the following command by using sudo:


systemctl restart ssh;

Lubuntu LVM Encrypted

 in GNU/Linux  tagged encrypted / lubuntu / lvm / lvm2 / lxde / swap / swapoff / ubuntu by

While trying to setup a lubuntu GNU/Linux that would use an encrypted LVM file-system we run into several problems that should have not been there.
For example, the installer would not continue as swap memory was not encrypted and it was blocking the operation.
An other issue was that the LVM support package was not installed by default although it is needed by the installer.

Our solution requires an active internet connection so that you can install the lvm2 package.

Methodology

After booting into the live session, before we started the installation process, we opened a terminal from the main menu (Start Menu) and executed the following two commands:


sudo apt-get install lvm2 -y;

sudo swapoff --all;

These two commands disabled all swap (so that we do not get the error that swap is not encrypted) and it installed the lvm2 package that is needed by the installer to create our LVM setup.

The following video presents the full successful installation procedure by making the changes before starting the procedure.

The next video, shows our attempts to fix the installation after encountering the errors instead of fixing them beforehand.