X11vnc and Linux Mint 19

TL;DR

Here are the steps to install X11vnc, and tunnel connections to remote machines through SSH.

Install and Configure SSH

See this post: Setup SSH for Local Access.

Install and Configure X11vnc

Firstly, I’d like the thank the author of this article, as the majority of the steps below come from his (or her) original post.

Install x11vnc:

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sudo apt install x11vnc

Create the directory that will hold the password and configuration files:

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sudo mkdir /etc/x11vnc

Create a password for the X11vnc server:

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sudo x11vnc --storepasswd /etc/x11vnc/vncpwd
Enter VNC password:
Verify password:
Write password to /etc/x11vnc/vncpwd?  [y]/n y
Password written to: /etc/x11vnc/vncpwd

Create a systemd service file for the X11vnc service:

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sudo xed /lib/systemd/system/x11vnc.service

Copy the text below into the x11vnc.service file:

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[Unit]
Description=VNC Server for X11
Requires=display-manager.service
After=display-manager.service

[Service]
Type=forking
ExecStart=/usr/bin/x11vnc -dontdisconnect -localhost -auth guess -forever -shared -noxdamage -repeat -rfbauth /etc/x11vnc/vncpwd -rfbport 5900 -bg -o /var/log/x11vnc.log
ExecStop=/usr/bin/killall x11vnc
Restart=on-failure
Restart-sec=5

[Install]
WantedBy=multi-user.target

Save and close the service file created, and copy it to /etc/systemd/system/:

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sudo cp /lib/systemd/system/x11vnc.service /etc/systemd/system/

Now edit the graphical.target file:

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sudo xed /lib/systemd/system/graphical.target

The final version will look like this:

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# SPDX-License-Identifier: LGPL-2.1+
#
# This file is part of systemd.
#
# systemd is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.

[Unit]
Description=Graphical Interface
Documentation=man:systemd.special(7)
Requires=multi-user.target
Wants=display-manager.service x11vnc.service
Conflicts=rescue.service rescue.target
After=multi-user.target rescue.service rescue.target display-manager.service
AllowIsolate=yes

Save and close the graphical.target file, and copy it to /etc/systemd/system/:

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sudo cp /lib/systemd/system/graphical.target /etc/systemd/system/

Enable the X11vnc service to start up on boot, and to kick off the service now:

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sudo systemctl daemon-reload
sudo systemctl enable graphical.target
sudo systemctl start x11vnc.service

Connecting to the X11vnc Host

Heed and Read: The Following steps should be done on the PC that will connect to the X11vnc host.

Open up your Terminal, and type the following:

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sudo apt-add-repository ppa:remmina-ppa-team/remmina-next
sudo apt update
sudo apt install remmina remmina-plugin-vnc remmina-plugin-rdp remmina-plugin-secret remmina-plugin-spice

Using the Linux Mint menu find “remmina” to open the main connection window:

Now add a new VNC Connection Profile:

Open a Terminal window, and enter the follow command to establish an SSH connection:

Note: If you have not followed the steps in my other post, you’ll need to do that first, and the come back to this.

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ssh -L 5901:127.0.0.1:5900 chucknorris@192.168.77.4 -p 2019

Double-click the Connection Profile you created earlier, and remotely connect to your X11vnc host:

The Rest of the Story

I’ve tried several different ways to remote control my Linux Mint PCs at home, and have not found a way I really like. Being honest, I really like Windows Remote Desktop (RDP), because it creates a “private” session; meaning if I am remotely connecting to my host PC, no one in the vicinity of my host PC can see what I am doing if the monitor happens to be on. Windows RDP will “lock” the host PC, and when I am back in front of the physical PC I can pick right back up where I have left off.

I’m still playing around with X2Go, but unfortunately X2Go does not play nice with Cinnamon (the primary Linux Mint desktop environment).

I have also been unsuccessful with xRDP, but I’ll keep experimenting with xRDP on Linux Mint.

If you have been able to get X2Go or xRDP to work on Linux Mint (with Cinnamon), please leave a comment on how you got that to work :-)

X11vnc + SSH

What I have been able to get working is Virtual Network Computing (VNC), specifically X11vnc.

I use this in conjunction with SSH (TCP forwarding & connection forwarding enabled). This will enable a secure connection with the VNC host over a secure SSH tunnel.

In this post, I will be taking you through the following:

1. Install and Configure SSH
2. Install and Configure X11vnc
3. Connecting to the X11vnc Host

Install and Configure SSH

I have a post I wrote on this with all the details, and you can find that post here.

Install and Configure X11vnc

Firstly, I’d like the thank the author of this article, as the majority of the steps below come from his (or her) original post.

Ok, so now let’s install the x11vnc server.

Start by opening a Terminal window, and entering the following command:

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sudo apt install x11vnc

Now that X11vnc server is installed, create the directory that will hold the password and configuration files. This will be a system-wide accessible folder. In the Terminal window, type the following command:

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sudo mkdir /etc/x11vnc

Next, create a password for the X11vnc server. VNC has a password limit of eight (8) characters (lame), so keep that in mind. Additionally, you will be prompted to enter the password twice.

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sudo x11vnc --storepasswd /etc/x11vnc/vncpwd
Enter VNC password:
Verify password:
Write password to /etc/x11vnc/vncpwd?  [y]/n y
Password written to: /etc/x11vnc/vncpwd

You are going to want the X11vnc server to start on boot, even if there is not a logged-in User. To accomplish that, create a systemd service file for the X11vnc service.

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sudo xed /lib/systemd/system/x11vnc.service

And copy the text below into the x11vnc.service file:

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[Unit]
Description=VNC Server for X11
Requires=display-manager.service
After=display-manager.service

[Service]
Type=forking
ExecStart=/usr/bin/x11vnc -dontdisconnect -localhost -auth guess -forever -shared -noxdamage -repeat -rfbauth /etc/x11vnc/vncpwd -rfbport 5900 -bg -o /var/log/x11vnc.log
ExecStop=/usr/bin/killall x11vnc
Restart=on-failure
Restart-sec=5

[Install]
WantedBy=multi-user.target

You’ll notice in the text above, the command parameter -localhost. This will force you to use an SSH tunnel in order to connect to your X11vnc host machine. Ultimately, only use your VNC connection over a “trusted” network, but if you were to enable this on a laptop, you want to be confident that you are not exposing your listening VNC connection on an “untrusted” network, for example if you were to connect to the Internet at a coffee shop.

If you followed the instructions in the “Install and Configure SSH” section above, you’ll have your firewall set up to only allow Local Area Network (LAN) connections to your host machine, and adding the -localhost parameter will afford an extra layer of security specific to your VNC connection.

For more information on the -localhost parameter, you can check out this post.

Save and close the service file created, and copy it to /etc/systemd/system/.

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sudo cp /lib/systemd/system/x11vnc.service /etc/systemd/system/

Now edit the graphical.target file.

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sudo xed /lib/systemd/system/graphical.target

You’ll change the line:

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Wants=display-manager.service

to:

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Wants=display-manager.service x11vnc.service

The full, final version will look like this:

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# SPDX-License-Identifier: LGPL-2.1+
#
# This file is part of systemd.
#
# systemd is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.

[Unit]
Description=Graphical Interface
Documentation=man:systemd.special(7)
Requires=multi-user.target
Wants=display-manager.service x11vnc.service
Conflicts=rescue.service rescue.target
After=multi-user.target rescue.service rescue.target display-manager.service
AllowIsolate=yes

Save and close the graphical.target file, and copy it to /etc/systemd/system/:

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sudo cp /lib/systemd/system/graphical.target /etc/systemd/system/

Finally, run the following commands in order to enable the X11vnc service to start up on boot, and to kick off the service now so you can move on to the next section.

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sudo systemctl daemon-reload
sudo systemctl enable graphical.target
sudo systemctl start x11vnc.service

Connecting to the X11vnc Host

There are multiple tools that you can use to connect to your X11vnc host. My favorite is Remmina. So here are the steps to get Remmina installed, and how to use it to remotely administer you X11vnc host.

The Remmina website has an excellent How to install Remmina guide, however it will be sightly different to make sure the VNC plugin gets installed as well.

Heed and Read: The Following steps should be done on the PC that will *connect to* the X11vnc host.

Open up your Terminal, and type the following:

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sudo apt-add-repository ppa:remmina-ppa-team/remmina-next
sudo apt update
sudo apt install remmina remmina-plugin-vnc remmina-plugin-rdp remmina-plugin-secret remmina-plugin-spice

Note: There is also a Remmina snap package if you prefer to go that route. Obviously, the instructions above do not apply to the snap package install.

With Remmina installed, create a Connection Profile in Remmina.

Using the Linux Mint menu find “remmina” to open the main connection window.

Now add a new VNC Connection Profile. For now just copy the settings (except the name, name it whatever you wish) in the screenshots below.

Here is brief explanation of the settings in the above screenshot:

• Protocol: Is a drop-down menu, and you will want to select “VNC - VNC viewer”. This is why remmina-plugin-vnc was used in the install command above.
• Server: Set this to “localhost:5901”. This works in conjunction with the SSH tunnel; forcing VNC to connect through the SSH tunnel.
• User password: You set the VNC password on this step, that is the same password you would use here.
• Color depth and Quality: Those settings are totally up to you.

After entering the settings, don’t forget to click “Save”. You should see your Connection Profile in the Main Connection Window.

Now open a Terminal window, and enter the follow command to establish an SSH connection. You will be prompted for a password, and this is the password of the User account on the remote PC.

Note: If you have not followed the steps in my other post, you’ll need to do that first, and the come back to this.

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ssh -L 5901:127.0.0.1:5900 chucknorris@192.168.77.4 -p 2019

The first time connecting you will receive this message:

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The authenticity of host '[192.168.77.4]:2019 ([192.168.77.4]:2019)' can't be established.
ECDSA key fingerprint is SHA256:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '[192.168.77.4]:2019' (ECDSA) to the list of known hosts.
chucknorris@192.168.77.4's password:
Last login: Thu Sep 12 22:59:54 2019 from 192.168.77.5

Now that the SSH connection is established, you can double-click the Connection Profile you created earlier, and remotely connect to your X11vnc host.

Conclusion

With the connection established, you can now remotely administer your X11vnc host.

Hope this is helpful :-)

Feel free to leave comments, or questions below.

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