A previous article mentioned using a keyboard shortcut to launch vnc, something I gained experience with while using the Raspberry Pi. VNC is a method of remote computer access, but why use two servers? The answer is that one attaches to an actual display “:0” and the other, a virtual “:1”.
X0tigervncserver is a TigerVNC Server which makes any X display remotely accessible via VNC, TigerVNC or compatible viewers. Unlike Xvnc(1), it does not create a virtual display. Instead, it just shares an existing X server (typically, that one connected to the physical screen).
- X11vnc is an alternative VNC server which can also provide direct control of the current X session. X0vncserver does not currently support clipboard sharing between the client and the server. TigerVNC's vncviewer also has a simple GUI when run without any parameters.
- Dec 01, 2009 VNC Comparison and Review: TightVNC vs UltraVNC vs RealVNC. Virtual Network Computing (VNC) requires a client (viewer) to connect to the remote computer. There are mainly three popular candidates for clients: RealVNC, TightVNC, and UltraVNC. We’ll do a simple comparison here and choose the best one.
- TigerVNC works on the client-server principle: a server shares its output (vncserver) and a client (vncviewer) connects to the server. Note Unlike in previous Red Hat Enterprise Linux distributions, TigerVNC in Red Hat Enterprise Linux 7 uses the systemd system management daemon for its configuration.
Using an actual display is essentially screen-sharing, where multiple users can manipulate the physical display simultaneously. To that end, a local user must be logged in and ready to share their desktop.
A virtual display is useful when one is using Linux in a “headless” configuration, where there is no local user involved.
For my purposes I did a “sudo apt-get install openssh-server x11vnc ssvnc tightvncserver” from the terminal.
While one could use the “/home/user/.vnc” folder to store configuration for both servers, I chose to make a separate one for x11vnc with commands:
mkdir ~/.x11vnc
x11vnc -storepasswd /home/user/.x11vnc/passwd
vncpasswd (and let is store its password in .vnc)
Setup the service from the instructions How to Install and Configure VNC on Ubuntu 16.04 | DigitalOcean.
After numerous attempts, I gave up on using SSL for the VNC security layer and opted for the more traditional SSH tunnel approach.
To connect to x11vnc I tunnel with command:
ssh -L 5902:localhost:5900 -N -f -l <user> <host>
While it’s this one for the tightvnc server:
ssh -L 5902:localhost:5901 -N -f -l <user> <host>
The command is saying map localhost port 5902 to remote port 590x. There is a relationship between the “port” and “VNC Host:Display” which is input in the form “host:display:port”. Display “0” is equivalent to port “5900” and display “1”, “5901”.
The display is essentially the last digit of the default VNC port number 590x. Using something like “192.168.0.2:1:5902” probably wouldn’t work since it’s like saying “192.168.0.2:1″ and 192.168.0.2:2” or “192.168.0.2::5901” and “192.168.0.2:1::5902”.
In some situations, “192.168.0.2:1” will work with the VNC client, and others “192.168.0.2::5901”. Just keep in mind the relationship and try things different ways.
Note that it isn’t necessary to use SSH or SSL. The purpose of both is to encrypt passwords so they aren’t transmitted across the network in “plain-text”. If using SSVNC with the tunneling commands, I mentioned earlier, be sure to set the “VNC Host:Display” to “localhost:2” and change the default encryption mechanism from “SSL” to “None”. The program will complain but it doesn’t know we’ve already handled the situation externally.
X11vnc Vs Tigervnc Pro
Now that there’s a vnc server running at boot on your Linux machine, you should be able to turn it on and just connect, even when it’s sitting at the login screen, right? Not necessarily. On Ubuntu variants using “network-manager”, check your network adapter settings “Network Tray Icon > Edit Connections > Ethernet/Wi-Fi subheading (your connection) > General”. Ensure that it is “Available to all users”. This seems to be the default on Ethernet but not Wi-Fi connections. If it isn’t available to all users, the network won’t connect before login.
X11vnc Vs Tigervnc
Additionally, it might be worthwhile to check your router/DSL modem/Cable modem/etc. settings for a “DHCP Reservation” option. It’s a nifty way to associate a MAC address to an I.P. so that you don’t have to touch any settings on the client computer and yet it is always assigned the same network address. Makes using VNC easier if you have trouble connecting to it by host-name.