HOWTO: Set up VNC server with resumable sessions

[Jeromy]

Below is a fix for users having trouble on AMD64 such as the "Segmentation Fault" or SystemException. I had all the same problems as mssm and kacheng with the vncserver on an amd64 system.

There is a bug in vncserver for AMD64 that has been discussed in detail over at the Debian forums.
http://lists.debian.org/debian-amd64.../msg00064.html (late 2004)
http://lists.debian.org/debian-amd64.../msg00255.html (late 2005)

The work-around is briefly discussed at Ubuntu 5.10 Support (GNOME) > AMD 64 Users :
http://ubuntuforums.org/archive/index.php/t-82548.html

Repeating the work-around, until there's a trusted source for vnc4server for amd64, you can download the fixed vnc4server and vncviewer as .deb packages from:

http://qt1.iq.usp.br/download/
vnc4server_4.0-7.3_amd64.deb [2.0M]
xvnc4viewer_4.0-7.3_amd64.deb [140K]

You then simply need to manually install them using dpkg from the download directory:

sudo dpkg -i vnc4server_4.0-7.3_amd64.deb
sudo dpkg -i xvnc4viewer_4.0-7.3_amd64.deb

Once installed, Tichondrius' HOWTO works perfectly following the original instructions.
It would be useful if a reference to the fix for AMD64 was included as the start of this how-to until vnc4server is available for amd64 by normal means.

Thanks!

[simon0t7]

excellent howto, got it to work and it doesn't have problems with refreshing the screen unlike the other vnc servers i've tried

[SSH Tech]

Okay, so this setup will allow me to start a new session on display 1. But can I resume an existing session on my physical display 0? Let's say I start a session at home normally on display 0. I start up gaim and firefox then lock the screen and go over to a friend's place. Can I resume this session using this method, or only start a new session?

[Tichondrius]

Okay, so this setup will allow me to start a new session on display 1. But can I resume an existing session on my physical display 0? Let's say I start a session at home normally on display 0. I start up gaim and firefox then lock the screen and go over to a friend's place. Can I resume this session using this method, or only start a new session?

No, this howto will not do that. I actually have VNC on display :0 working as well using x11vnc which is a VNC extension to the regular X server (e.g. xorg). I plan to publish a separate howto on that. Stay tuned.

[Tichondrius]

Below is a fix for users having trouble on AMD64 such as the "Segmentation Fault" or SystemException. I had all the same problems as mssm and kacheng with the vncserver on an amd64 system.

There is a bug in vncserver for AMD64 that has been discussed in detail over at the Debian forums.
http://lists.debian.org/debian-amd64.../msg00064.html (late 2004)
http://lists.debian.org/debian-amd64.../msg00255.html (late 2005)

The work-around is briefly discussed at Ubuntu 5.10 Support (GNOME) > AMD 64 Users :
http://ubuntuforums.org/archive/index.php/t-82548.html

Repeating the work-around, until there's a trusted source for vnc4server for amd64, you can download the fixed vnc4server and vncviewer as .deb packages from:

http://qt1.iq.usp.br/download/
vnc4server_4.0-7.3_amd64.deb [2.0M]
xvnc4viewer_4.0-7.3_amd64.deb [140K]

You then simply need to manually install them using dpkg from the download directory:

sudo dpkg -i vnc4server_4.0-7.3_amd64.deb
sudo dpkg -i xvnc4viewer_4.0-7.3_amd64.deb

Once installed, Tichondrius' HOWTO works perfectly following the original instructions.
It would be useful if a reference to the fix for AMD64 was included as the start of this how-to until vnc4server is available for amd64 by normal means.

Thanks!

Done. Thanks !

[CosMix]

Hey there,

Im just curious about one thing...can i set another port on which vnc server would accept connections in order to be able to have two or more simultaneous connections on one vnc server ?...like...can i add another port in this conf file ?


service Xvnc
{
type = UNLISTED
disable = no
socket_type = stream
protocol = tcp
wait = yes
user = root
server = /usr/bin/Xvnc
server_args = -inetd :1 -query localhost -geometry 1024x768 -depth 16 -once -fp /usr/share/X11/fonts/misc -DisconnectClients=0 -NeverShared passwordFile=/root/.vncpasswd
port = 55566
port = can i add another port here?
}

And btw, great howto! Wish there were more ppl like you...willing to help and above all, able to help.

Gorazd

[Tichondrius]

Hey there,

Im just curious about one thing...can i set another port on which vnc server would accept connections in order to be able to have two or more simultaneous connections on one vnc server ?...like...can i add another port in this conf file ?


service Xvnc
{
type = UNLISTED
disable = no
socket_type = stream
protocol = tcp
wait = yes
user = root
server = /usr/bin/Xvnc
server_args = -inetd :1 -query localhost -geometry 1024x768 -depth 16 -once -fp /usr/share/X11/fonts/misc -DisconnectClients=0 -NeverShared passwordFile=/root/.vncpasswd
port = 55566
port = can i add another port here?
}

And btw, great howto! Wish there were more ppl like you...willing to help and above all, able to help.

Gorazd

Let me clarify that every X-windows server manges one display. Your actual monitor is display :0 and is controlled by Ubuntu's default X-windows server. The Xvnc program is also an X-windows server which controls display :1 (which is a virtual diplay that can be projected to a VNC client) according to how we set it up in this guide. It also serves as a VNC server which listens on port 5901.

If you want more than one VNC client to share the display you can remove the -NeverShared option from the server_args line in the script. But that means that all the clients still connect to the server on the same port 5901 and see the exact same display. In fact, if any client moves the mouse for example, then the other clients will see the mouse cursor move as well.

If you want to allow more than one concurrent sessions, than you need to run another instance of Xvnc on a different display. To do that, make a copy of the Xvnc script in /etc/xinetd.d called Xvnc2 (in the same directory), and in the new file change the display to :2 and the port to 5902. Now restart xinetd as shown in step 6 of the howto, and you will have two Xvnc servers running, each waiting for a connection on a different port and managing a different display. So you could have two users running independent sessions, each one on a different virtual display.

[edsel6502]

Hi there I'm having a problem resuming an old session.

What I do is login via GDM then quit the vncviewer program and then try to reconnect. Instead of letting me resume, it gives me the GDM login again.

The following is the args I'm passing Xvnc. I had to remove the -fp option as it refused to connect saying that I did not have a fixed font.

service vnc
{
type = UNLISTED
disable = no
socket_type = stream
protocol = tcp
wait = no
user = root
server = /usr/bin/Xvnc
server_args = -inetd :1 -query localhost -geometry 1280x1024 -depth 16 -DisconnectClients=0 -IdleTimeout=0 -NeverShared -SecurityTypes=none
port = 5901
}

Update:

Ok I'm stumped. It seems to behave as expect when run from the commandline. Multiple tests to localhost:2 confirms it.

Xvnc :2 -query localhost -geometry 1280x1024 -depth 16 -DisconnectClients=0 -IdleTimeout=0 -NeverShared -SecurityTypes=none

The only thing it seems to be choking on is launching from xinetd which makes it want to login via GDM each and every time...

[Tichondrius]

I think it might be the fact that you set Idle timeout to zero, so try changing that option. I understand that when you disconnect you don't mean that you explicitly log out from the gnmoe session, right ?

Also you should restart xinetd and kill all the Xvnc processes by doing step 5, because sometimes things get messed up and xinetd just keeps spawning more and more Xvnc process instead of waking up the old one.

[edsel6502]

When I quit I just quit the vncviewer application. I am still logged in via my windowmanager session.

I also do a cold boot. To make sure everything is running properly.

I'll try it without the IdleTimeout=0 But I really really need that vnc session not to timeout.

Update:

Nope that didn't work.

I think I might have to force a script to launch on boot.