how tostart VNCserver
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Question / Problem
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how tostart VNCserver
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Solution
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Overview of VNC
VNC, or Virtual Networked Computing, is a way of
controlling a remote computer just as though you are sitting in front of
it. In the Windows world it
is also known as remote desktop but
it's normally referred to as VNC in the Linux world. All that happens is
that you connect using a VNC client to a
remote computer running
the VNC server, then an image of the remote desktop is transmitted to
your local computer and you can see and control the desktop
just as
though you are there since all keyboard and mouse commands are sent from
your client machine to the server.
Gnome Remote Desktop
If
you are running the Gnome desktop on Fedora Core then you already have a
VNC server built in. Click on the Fedora icon > Desktop >
Preferences >
Remote Desktop to open the dialog shown.
Gnome
remote
desktop
The screen is pretty self explanatory but basically when
set up this way another computer can connect to your computer using the
command listed on
the dialog. There are a few important things to
note, you must open port 5900 on the server for this to work since by
default the Gnome Remote
Desktop (called vino) listens on this port,
also the person connecting will see the same session that you are
currently logged in as. This means that
any programs you have open
will also be visible to the client, of course this is very useful if you
are helping someone remotely.
A more flexible way to use VNC is
to install the VNC server and client software via yum, these are rpm's
based on
RealVNC.
vncserver and vncviewer
Check
what's installed
First check if you already have them installed
on your system, open a terminal and type:
$ rpm -qa|grep
vnc
vnc-server-4.1.1-36
vnc-4.1.1-36
If you get an
output something like this then you're all ready, if not you need to
install them via yum.
Add a user(s)
Next we need to add at
least 1 VNC user, open the file /etc/sysconfig/vncservers as root and
add the information shown:
$ vi /etc/sysconfig/vncservers
#
The VNCSERVERS variable is a list of display:user pairs.
#
#
Uncomment the lines below to start a VNC server on display :2
# as my
'myusername' (adjust this to your own). You will also
# need to set
a VNC password; run 'man vncpasswd' to see how
# to do that.
#
#
DO NOT RUN THIS SERVICE if your local area network is
# untrusted!
For a secure way of using VNC, see
#
<URL:http://www.uk.research.att.com/archive/vnc/sshvnc.html>.
#
Use "-nolisten tcp" to prevent X connections to your VNC server via
TCP.
# Use "-nohttpd" to prevent web-based VNC clients
connecting.
# Use "-localhost" to prevent remote VNC clients
connecting except when
# doing so through a secure tunnel. See the
"-via" option in the
# `man vncviewer' manual page.
VNCSERVERS="1:bobpeers"
VNCSERVERARGS[1]="-geometry
1024x768 -depth 16"
The important part is the
VNCSERVERS="1:bobpeers", this sets up a users for the vnc server, you
can add as many as you like here. The VNCSERVERARGS[1]
line refers
to the arguments for user 1, in this case the only user. Geometry sets
the size and depth sets the colour depth, you can adjust these to
suit
your preferences but in my case the client machine has a resolution of
1024x768 and the depth 16 makes the connection a bit faster since the
less
information that needs to be sent the more responsive the
session will feel.
Knowing which port to use
It's also
important to note the session number user as this will tell us which
port vncserver
will listen on. Remember the Gnome Remote Desktop
asked us to use
computername:0 as the connection string, the number needs to be added to
5900 to get the listening port. In this case we need to use
port
5901 since we are using session 1. In the same way we could use any
number, for example:
VNCSERVERS="2000:bobpeers"
VNCSERVERARGS[2000]="-geometry
1024x768 -depth 16"
In this case we need to use port
5900+2000 so port 7900.
Setting a password
To add some
security we need to add a password that must be given before a
connection can be established, open a terminal and type:
$
vncpasswd
Password:
Verify:
This creates a hidden
folder called .vnc in your home folder containing the password file.
Starting
the server and startup options
To start the server we type the
command 'vncserver' and the session you wish to start (if you have set
up more than 1 entry in the
/etc/sysconfig/vncservers file:
$ vncserver :1
Starting
VNC server: 1:bobpeers
New 'linux.bobpeers:1 (bobpeers)' desktop is
linux.bobpeers:1
Starting applications specified in
/home/bobuser/.vnc/xstartup
Log file is
/home/bobuser/.vnc/linux.bobpeers:1.log
[ OK ]
Now the server is started and a user could connect,
however they will get a plain grey desktop by default as the connection
will not cause a new
session of X to start by default, to fix this
we need to edit the startup script in the .vnc folder in your home
directory.
$ vi
~/.vnc/xstartup
#!/bin/sh
# Uncomment the following two
lines for normal desktop:
unset SESSION_MANAGER
exec
/etc/X11/xinit/xinitrc
[ -x /etc/vnc/xstartup ] && exec
/etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb
$HOME/.Xresources
xsetroot -solid grey
vncconfig -iconic &
xterm
-geometry 80x24+10+10 -ls -title "$VNCDESKTOP Desktop" &
twm
&
As the file says make sure the two lines at the top are
uncommented by removing the leading # sign. Next we need to restart
vncserver to pick up
the changed we just made. To restart the
vncserver we need to kill the process and start a new one as root:
$
vncserver -kill :1
Killing Xvnc process ID 13728
$
vncserver :1
Starting VNC server: 1:bobpeers
New 'linux.bobpeers:1
(bobpeers)' desktop is linux.bobpeers:1
Starting applications
specified in /home/bobuser/.vnc/xstartup
Log file is
/home/bobuser/.vnc/linux.bobpeers:1.log
[ OK ]
Using vncviewer
To start the viewer type:
$
vncviewer localhost:5901
This open a dialog as shown for us
to enter our password we set earlier, enter the password and you should
now see a copy of your desktop. Note
that unlike the Gnome Remote
Desktop this has started a new session of X so any applications open on
the host machine are not visible to the new
session, it's basically a
whole new logon running at the same time.
If you just type
'vncviewer'
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Applies to |
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Linux
,Red Hat Linux
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Rank It |
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