#rev 2020-09-15 gfreudig
## page was renamed from x11vnc
= x11vnc =
`x11vnc` allows you to view and interact remotely with an existing desktop session of yours. In case you have no running session on the physical display and need to login graphically, please contact [[mailto:support@ee.ethz.ch|support]] and provide the name of the host you need to access.

{{{{#!wiki important
'''Please note:''' While you are working with `x11vnc`, someone in your office can watch your actions on the local monitor of your computer. 
}}}}

== Other use cases ==
The normal [[RemoteAccess/VNC|vncserver]] relies on the [[https://www.mesa3d.org/|OpenGL implementation called Mesa]], which is not hardware-accelerated in a VNC session. In case you see errors similar to:
{{{
"Xlib:  extension "GLX" missing on display ":1".
}}}
you might want to use x11vnc.
The GLX driver in use and whether hardware acceleration ("direct rendering") is active can be shown with
{{{#!highlight bash numbers=disable
glxinfo |grep -E 'vendor string|direct rendering'
}}}


== How do I start x11vnc? ==

In a terminal window in your existing desktop session start a `x11vnc` server with password protection. If you already have a password file `~/.vnc/passwd` from `vncserver` you must enter: 

{{{
pmuster@zampano:~$ x11vnc -usepw -q

The VNC desktop is:      zampano:0
PORT=5900
}}}

To start x11vnc in a ssh terminal not belonging to the existing desktop session you must specify the X11 display:
{{{
pmuster@zampano:~ $ x11vnc -usepw -q -display :0

The VNC desktop is:      zampano:0
PORT=5900
}}}

If you don't have a password file from vncserver usage you will be prompted for one:
{{{
pmuster@zampano:~ $ x11vnc -usepw -q
Enter VNC password:
Verify password:
Write password to /home/pmuster/.vnc/passwd?  [y]/n y
Password written to: /home/pmuster/.vnc/passwd

The VNC desktop is:      zampano:0
PORT=5900
}}}

== Connect with VNC Viewer ==
After setting everything up you can connect to it with a VNC viewer. If you are outside ETH you need to either use VPN or tunnel the VPN connection trough a SSH. See [[RemoteAccess|remote access documentation]] for details.

{{attachment:vnc.PNG}}

After connection, if you log out or close the window the process will be stopped.