Enabling VNC

[Kevin J. Cummings]

Jeremy Conlin wrote:
> On 2004-10-19 16:32:27 -0400, "Kevin J. Cummings" 
> <cummings at kjchome.homeip.net> said:
> 
>> Jeremy Conlin wrote:
>>
>>> My xstartup looked nearly the same.  I uncommented the exec... line 
>>> earlier and just now uncommented the unset... line.  After rebooting 
>>> (and restarting vncserver) and closing the firewall it came up just 
>>> the way I expected it to.  Now, how can I configure the firewall to 
>>> accept vnc connections without turning it off?  And how can I get 
>>> vncserver to start on boot?
>>
>>
>> What has been discussed so far is how to create a VNC connection to a 
>> new virtual desktop (thus the :1 in the display name).
>>
>> I think what you are looking for is how to control your console X11 
>> desktop from a remote machine.
> 
> What I need is to see the GUI desktop of my FC2 machine from a remote 
> machine.  I would prefer to do this without a client (i.e. using only 
> X11) if possible; if not I can use a VNC client.

Yes, that's what I said!  B^)

>> This can be done with a small change to your X11 config.
>>
>> In your Section "Module", include the following:
>>
>>     # Load the REALVnc module
>>     Load    "vnc"
>>
>> Then, later on in your Section "Screen", you will need a line like:
>>
>>     Option    "passwordFile" "/root/.vnc/passwd"
> 
> Where are these sections?  I have never changed my X11 config.

Your xorg.conf file (usually found in /etc/X11 directory) is comprised 
of various "sections".

It begins with a *lot* of comments describing the various copyrights and 
then a description of the file layout.  (You should read it!)  B^)

Essentially, you have a "ServerLayout" to start with.  This describes 
which other "Sections" make up your X server.  It defines a "Screen" and 
a number of "InputDevice"s.  You can have a number of ServerLayouts, 
but, I beleive that the first one is the important one unless you invoke 
your X server with the -layout option.

After this, is the "Files" section which tells the X server where to 
find some important files it might need (including the path to the 
various "modules" used by the server).

The "Modules" section tells the server which Modules you want loaded. 
These are like shared libraries or kernel modules that help provide 
functionality to the X server.  "vnc" is one such module that allows a 
"vnc client" to be able to connect to your X server and control it 
remotely.  I beleive that the actual name of the module is REAL VNC.

This is what makes it different from the vncserver service that you  may 
or may not start from /etc/init.d.  The vncserver service starts a 
virtual X11 desktop, while the REAL VNC module allows VNC like you are 
used to seeing on that "other" PC operating system.  B^)

There are more "Sections" to your xorg.conf file.  I will leave figuring 
out most of them up to you as an exercise in reading your own xorg.conf 
file.  I wish it was better documented so I knew *what* all the options 
were everywhere, but for now that is most of what you need to change.

The last part you need to change is in the "Screen" section that your 
Layout uses.  This Screen section includes your videao device name, your 
monitor type, and has subsections that help configure all of the 
supported screen sizes (Modes).  Here is where you need to specify where 
the "password" file will reside for your vnc session.  The password file 
is necessary to keep just anyone from attaching to your X11 session and 
reeking havoc with your machine.  Especially if you keep root windows 
open on your desktop!

I put mine in /root/.vnc/passwd (a similar location to where the 
vncserver service puts a user's password file, but this is for the root 
user).  I must admit, I cheated.  I just copied the password file from 
my home directory (~/.vnc/passwd) to the root directory.  But, it works 
for me.  All you need to know is the "DISPLAY" number of the X11 session 
you want to connect to, and the password stored in your 
/root/.vnc/passwd file in order to connect.

You did know that it is possible to run multiple X servers on your 
machine at any given time, right?  I once had 3 different X servers 
running on an old K6-2/3D 400MHz machine with only 256MB of ram, each 
server running with a different color depth (8, 16, 24).  It was kind of 
a proof of concept thingy.  Each server had a different DISPLAY number. 
  The first was :0.0, the second was :1.0, the third was :2.0.  Then I 
started up a vncserver service, and it was assigned DISPLAY :3.0.  (Of 
course, my machine paged a lot after that, but the point was to see how 
all of the xservers could run together and be attached to via vnc clients.)

>>
>> This should allow to to  connect to your :0 X11 display and control it 
>> via VNC.
> 
> 
> Thanks for your help.  Someday I will become proficient at Linux (I hope).

Practice make perfect.  I've been playing with Linux since kernel 
release 0.12 on an old 386 25Mhz machine when I found out that my 60MB 
hard drive was really a 70MB hard drive, and Linux could be installed on 
  the extra 10MB of space without disrupting DOS 3.2 (which needed 
special disk drivers to access any more than 32MB....)

> Jeremy

I hope this make things clearer....

-- 
Kevin J. Cummings
kjchome at rcn.com
cummings at kjchome.homeip.net
cummings at kjc386.framingham.ma.us