VNC Server setup on Linux

Jeff Vincent JVINCENT "at"
Tue, 15 Jan 2002 18:57:53 +0000

The grey screen usually means that either the display manager isn't
running, xdmcp is not enabled or the client doesn't have access.

I BELIEVE that once Xvnc runs, it contacts the display manager (if it
is running) using the XDMCP protocol on port 177 (if xdmcp is enabled)
of the machine you are on (if querying localhost) or the machine/chooser
that response via the broadcast request.  Once contacted, if Xaccess (or
equivalent) says it is okay, the display manager starts a new session
for Xvnc which is then displayed to the remote client.

Find out which display manager is running ('ps -A | grep dm' usually
does it for me - gdm, xdm, kdm are the most common), check your Xaccess
as David said and the configuration files of the display manager that is
running for xdmcp.

Let us know what you determine.


>>> joel.sherrill "at" 01/15/02 11:06AM >>>
Dumas Patrice wrote:
> Hi,
> I tried to do what the instructions are about in the past, but never
> succeded... I hope I will, now. Well, I tested, it works well !

Thanks all.  This certainly seems to be closer for me but I must
still be missing something.  Perhaps something broken from my previous
attempts at this.  :(

I am on RedHat 7.1

I now have gotten far enough to get a grey screen on each of the
ports I have tried but no login screen.  I am getting a message
like this in /var/log/messages each time I get a grey screen 
so I must be close. :)

<date> <host> gdm[PID]: Failed to start X server several times in 
a short time period: disabling display:0

Any ideas on something I might have missed.?



> > Hi all,
> >
> > With the recent threads on setting up VNC Server on Linux systems,
I have put
> > everything that Jeff Vincent said on my web site. This works for
RH6.2, 7.1
> > and 7.2. If anyone has setups for other systems, it would be
appreciated. If
> > you find anything wrong with it, can you let me know.
> - I cannot find any 'vncserver.*' on my system (redhat 7.0 with some
7.1 and
> 7.2 packages)
> - I use gdm, and not xdm nor kdm. Thus the instructions for setting
> are different, and are, if not wrong
> in gdm.conf, in the [xdmcp] section, there should be Enable=true
> - to have xdm, gdm or kdm reread their config file, sending a SIGHUP
should be
> fine.
> - I suggest you to rearrange your instruction the following way:
instead of 2)
> 3) and 4), only one point explaining how to set up XDMCP. For

According to ps eax | grep dm, I am running gdm.
>         3) enable XDMCP
>                 a) xdm, old kdm
>                         i) RedHat 6.2, 7.1, 7.2
>                         edit '/etc/X11/xdm/xdm-config' and comment
out the line '!
> DisplayManager.requestPort: 0' (should be the last line)
>                         edit /etc/X11/xdm/Xaccess and uncomment the
line '*        #any
> host can get a login window'

I did these.

>                 b) new kdm - edit 'kdmrc' and enable XDMCP on port
>                         i) RedHat 7.2 - '/etc/kde/kdm/kdmrc'

The only kdmrc I see is in /etc/X11/xdm and I don't know what to do to
it.  I
don't think I am running it anyway.

>                 c) gdm - edit gdm.conf and in the section [xdmcp] set
>                         i) Redhat 7.1, 7.2 - '/etc/X11/gdm/gdm.conf'

I have set Enable=true and Enable=1 with the same resault.

> (note: maybe I said a mistake, and for the new kdm, one should also
> Xaccess)
> Pat
> To unsubscribe, mail majordomo "at" with the line:
> 'unsubscribe vnc-list' in the message BODY
> See also: 

Joel Sherrill, Ph.D.             Director of Research & Development
joel "at"                 On-Line Applications Research
Ask me about RTEMS: a free RTOS  Huntsville AL 35805
   Support Available             (256) 722-9985
To unsubscribe, mail majordomo "at" with the line:
'unsubscribe vnc-list' in the message BODY
See also: 
To unsubscribe, mail majordomo "at" with the line:
'unsubscribe vnc-list' in the message BODY
See also: