HOWTO: Set up VNC server with resumable sessions - KUBUNTU VERSION

paperdiesel · 02:22 PM

This guide is very similar to the Gnome Ubuntu HOWTO, located here:

http://ubuntuforums.org/showthread.php?t=122402

I have borrowed a lot of the notes from that author, only changing things to work for Kubuntu users. Most of the credit for the info goes to the author of that post. If you are having problems, I strongly recommend browsing through that thread first.

This guide is intended for Kubuntu users, and details how to enable Xdmcp for your KDE session. It was written using Kubuntu 6.06 (i386) as a reference. In the steps, I use kate as the text editor, but you can use whatever editor you prefer. In reality I use vi, but most people don't know vi commands so I stick with kate in these examples.

Required packages:

To make sure you have the proper software installed, execute the following:

Type in a terminal:

Code:

sudo apt-get install vnc4server xinetd xvncviewer

The latest versions are:
vnc4server: Xvnc Free Edition 4.1.1
xinetd: xinetd Version 2.3.14 libwrap loadavg
xvncviewer: VNC viewer version 3.3.7 - built Feb 20 2006 12:04:05

If you're using previous versions of any of these packages, there's no guarantee this will work. (Actually, there's no guarantee this will work anyway, but if you use versions below what I indicated, then you're just making it harder on yourself

)

WARNING: Make sure you install vnc4server and NOT vncserver. These packages ARE different, and the latter will NOT work correctly.

Note to AMD64 users: The current version of vnc4server in the repositories has a bug, so you need to download and install the fixed vnc4 packages as shown below:

Code:

wget http://qt1.iq.usp.br/download/vnc4server_4.0-7.3_amd64.deb
wget http://qt1.iq.usp.br/download/xvnc4viewer_4.0-7.3_amd64.deb
sudo dpkg -i vnc4server_4.0-7.3_amd64.deb
sudo dpkg -i xvnc4viewer_4.0-7.3_amd64.deb

THE STEPS:

1. ENABLE XDMCP IN KDE

Type in a terminal:

Code:

sudo kate /etc/kde3/kdm/kdmrc

At the very bottom of the file, you'll see this section:

Code:

[Xdmcp]
Enable=false
Willing=/etc/kde3/kdm/Xwilling

Change it to look exactly like this:

Code:

[Xdmcp]
Enable=true
Port=177
Xaccess=/etc/kde3/kdm/Xaccess
Willing=/etc/kde3/kdm/Xwilling

Save the file and quit. Then type this in your terminal:

Code:

sudo kate /etc/kde3/kdm/Xaccess

This is a big file and can be confusing, so make sure you do this exactly as shown. Scroll down and find this line:

Code:

#*                                       #any host can get a login window

Remove the # from the beginning of that line, so it looks like this:

Code:

*                                       #any host can get a login window

Then find this line:

Code:

#*               CHOOSER BROADCAST       #any indirect host can get a chooser

Remove the # from the beginning of that line, so it looks like this:

Code:

*               CHOOSER BROADCAST       #any indirect host can get a chooser

Save the file and quit out of KATE.

Now we need to restart the KDM process so it will re-read the configuration file. The easiest way to do this is to just reboot the machine. The quickest is to do the following:

Code:

ps -ef | grep kdm

This will print out a list of processes with the letters 'kdm' in the name. Find the one that looks like the following (Specifically the one that ends in /usr/bin/kdm):

Code:

root    4530      1     0 0:09:20 ?          00:00:00 /usr/bin/kdm

See the number right after root? 4530 in my example, you will almost certainly have a different number. That's the process ID or PID. Type the following command to restart kdm (Substituting the PID number you have for the 4530 in my example):

Code:

sudo kill -HUP 4530

2. SET THE VNC PASSWORD

Type this in a terminal:

Code:

sudo vncpasswd /root/.vncpasswd

3. ADD VNC SERVICE TO XINETD

Type this in a terminal:

Code:

sudo kate /etc/xinetd.d/Xvnc

Enter this in to the new file:

Code:

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 = 5901
}

I recommend leaving all of that code alone, but you can safely change the 1024x768 to be a bigger or smaller resolution for your Xvnc window, depending on what you want. You can also change the depth, but understand that increasing the depth bits will cause more bandwidth to be used over your network, which could slow down your VNC experience considerably.

4. RESTART XINETD

If the following code does not work, try rebooting:

Code:

sudo /etc/init.d/xinetd stop
sudo killall Xvnc
sudo /etc/init.d/xinetd start

Don't worry if you see a message like "Xvnc: no process killed". This just means there was no open, active session of VNC running at the time. This is expected and is normal.

5. TEST

If you followed all of the above steps correctly, you should now be able to test your VNC server. Type the following in a terminal:

Code:

vncviewer localhost:1

You should be prompted for the VNC password, and then see the KDM login screen where you can login and start a new X session. If that works, you can now go ahead and try to connect from remote machine using your favorite VNC client (remember to first close the local vncviewer we started above). Remember to use the VNC server machine's domain name or IP address, followed by :1 (e.g. 192.168.0.100:1). If connecting locally as shown above works, but connecting remotely fails, then this means you have a problem with a firewall which is blocking some ports. See the notes below about how to deal with that.

Note about ports: The VNC server set up as shown uses TCP port 5901. If you are using firewall software (e.g. firestarter) on that machine, you need to allow incoming connections on this port. If you are using a router which assigns your machine a private address (e.g. 192.168.0.100) which is not accessible from the internet, then you need to forward TCP port 5901 from the router to this machine.

Note about security: This setup allows any user to start an X-session remotely by logging in using his regular password (after starting the VNC connection using the VNC password), so if the user disconnects without logging out, any other user which knows the VNC password can connect afterwards and resume the same session that the first user started. So if you do not want to log out before disconnecting, it's advisable to at least lock your VNC X-session screen. Also note that while a remote user is connected thru VNC, no other connection will be accepted. An idle VNC client will be disconnected after one hour, but this can be changed by using the "-IdleTimeout" option in the server_args line in /etc/xinetd.d/Xvnc. For example, you can add "-IdleTimeout 300" to change it to 5 minutes.

reference links:
Gnome VNC howto: http://ubuntuforums.org/showthread.php?t=122402
Xdmcp in kdm: http://klomdark.servebeer.com:8081/M...px?MsgNum=1967

Good luck!

master_b

Hi paperdiesel

Thanks for the Kubuntu HowTo for vnc4server.

I've been trying to get remote access (over my home LAN) to desktop:0 ( actual desktop) of a remote "headless" PC ie no monitor, mouse or keyboard, but its NVidea TV out is connected to a TV and I can view the "cloned" desktop ( and TV output) on that.

Can successfully remotely access the pc using NX ( better than vnc, Krfb etc in my opinion) but none of those allow access to desktop:0, whereas vnc4 will ( at least according to its website).

Will post re my success or otherwise.

Bill

master_b

Follow-up:-

Worked perfectly except that I get a grey desktop. Remember having same problem eons ago with vnc but forget fix. Will figure it out and post.

In addittion, NX still works without problems, whereas when I had plain vnc installed, NX wouldn't work when the vncserver was running.

Bill

paperdiesel

Hey Bill,

If you want to use VNC to view display :0, I'd recommend x11vnc. I used it a while back, and if I remember correctly, it acts as a VNC extension to the X server, and loads inside your xorg.conf file and allows you to VNC in to the main display.

I've also heard about people using vnc4server and getting grey screens. But if you're trying to use vnc4server to display :0, that might be why you're getting a grey screen. Try x11vnc and let me know if it works.

master_b

Hi paperdiesel

thanks for the reply.

Have tried several "HowTos" for remote connecting to desktop:0, including x11vnc, but your instructions herewith are the only one's that I've found for Kubuntu.

Problem is that many of the Ubuntu "Howtos" give instructions to use various Gnome Menu items that just don't exist with Kubuntu/KDE, and fail to name the actual config files that are altered.

From past experience with vnc, which I haven't used since discovering NX, I have vague recollections that in order to fix the "grey screen" problem, a config file has to be altered to include the starting of the desired window manager, in this case kde.

When I get time I'll dig through my old install notes and try to find the info. Have "googled" to no avail. I think that this "grey screen" problem can occur regardless of whether you are using Krdc, vnc, x11vnc etc.

Bill

paperdiesel

Ah, well if that's the case, the only config file I know that sounds similar to what you describe is the xstartup file, located in ~/.vnc/

Open up ~/.vnc/xstartup and scroll to the bottom of the file. If you see a line that looks like:

Code:

twm &

Change it to:

Code:

startkde &

.

See if that helps.

glave

Just for reference, I had a problem with myself getting a connection reset by peer.

http://ubuntuforums.org/showthread.p...th#post1869576

Following the above advice (adding my fonts path to the config) I was able to get things working smoothly!

pickarooney

I get the following when running vncviewer localhost:1 on Kubuntu 6.10 64-bit, qfter forcing the dpkg files to install without deps.

Code:

VNC viewer for X version 4.0 - built Oct 19 2005 20:19:45
Copyright (C) 2002-2004 RealVNC Ltd.
See http://www.realvnc.com for information on VNC.

Mon Dec 25 00:51:54 2006
 main:        unable to connect to host: Connection refused (111)

Same if I try to connect to 192.168.1.100 (my PC) or when changing the number after teh colon to 0 or 15900 (my open VNC port, set as such in the setup file).

leprasmurf

great guide, I'll have to try it with edubuntu.

deserthowler · 01:38 AM

I am running Kubuntu Dapper.

I had TightVNC installed so I uninstalled it and the other VNC stuff. I installed everything just as you said in the WIKI. It worked just as stated. I got the sign-in screen just as I wanted. I had the monitor running on the server computer and got a log-in window there too. I ended up running 2 sessions simultaneously ... one on the client and one on the server computer.

I got a lot of error messages from kate so I went to nano and wrote the configuration files.

GREAT WIKI!!!!

It worked. That's all I can say.

Earl

September 17th, 2006	#1
paperdiesel Way Too Much Ubuntu Join Date: Oct 2005 Beans: 243 Ubuntu 7.10 Gutsy Gibbon	HOWTO: Set up VNC server with resumable sessions - KUBUNTU VERSION This guide is very similar to the Gnome Ubuntu HOWTO, located here: http://ubuntuforums.org/showthread.php?t=122402 I have borrowed a lot of the notes from that author, only changing things to work for Kubuntu users. Most of the credit for the info goes to the author of that post. If you are having problems, I strongly recommend browsing through that thread first. This guide is intended for Kubuntu users, and details how to enable Xdmcp for your KDE session. It was written using Kubuntu 6.06 (i386) as a reference. In the steps, I use kate as the text editor, but you can use whatever editor you prefer. In reality I use vi, but most people don't know vi commands so I stick with kate in these examples. Required packages: To make sure you have the proper software installed, execute the following: Type in a terminal: Code: sudo apt-get install vnc4server xinetd xvncviewer The latest versions are: vnc4server: Xvnc Free Edition 4.1.1 xinetd: xinetd Version 2.3.14 libwrap loadavg xvncviewer: VNC viewer version 3.3.7 - built Feb 20 2006 12:04:05 If you're using previous versions of any of these packages, there's no guarantee this will work. (Actually, there's no guarantee this will work anyway, but if you use versions below what I indicated, then you're just making it harder on yourself ) WARNING: Make sure you install vnc4server and NOT vncserver. These packages ARE different, and the latter will NOT work correctly. Note to AMD64 users: The current version of vnc4server in the repositories has a bug, so you need to download and install the fixed vnc4 packages as shown below: Code: wget http://qt1.iq.usp.br/download/vnc4server_4.0-7.3_amd64.deb wget http://qt1.iq.usp.br/download/xvnc4viewer_4.0-7.3_amd64.deb sudo dpkg -i vnc4server_4.0-7.3_amd64.deb sudo dpkg -i xvnc4viewer_4.0-7.3_amd64.deb THE STEPS: 1. ENABLE XDMCP IN KDE Type in a terminal: Code: sudo kate /etc/kde3/kdm/kdmrc At the very bottom of the file, you'll see this section: Code: [Xdmcp] Enable=false Willing=/etc/kde3/kdm/Xwilling Change it to look exactly like this: Code: [Xdmcp] Enable=true Port=177 Xaccess=/etc/kde3/kdm/Xaccess Willing=/etc/kde3/kdm/Xwilling Save the file and quit. Then type this in your terminal: Code: sudo kate /etc/kde3/kdm/Xaccess This is a big file and can be confusing, so make sure you do this exactly as shown. Scroll down and find this line: Code: #* #any host can get a login window Remove the # from the beginning of that line, so it looks like this: Code: * #any host can get a login window Then find this line: Code: #* CHOOSER BROADCAST #any indirect host can get a chooser Remove the # from the beginning of that line, so it looks like this: Code: * CHOOSER BROADCAST #any indirect host can get a chooser Save the file and quit out of KATE. Now we need to restart the KDM process so it will re-read the configuration file. The easiest way to do this is to just reboot the machine. The quickest is to do the following: Code: ps -ef \| grep kdm This will print out a list of processes with the letters 'kdm' in the name. Find the one that looks like the following (Specifically the one that ends in /usr/bin/kdm): Code: root 4530 1 0 0:09:20 ? 00:00:00 /usr/bin/kdm See the number right after root? 4530 in my example, you will almost certainly have a different number. That's the process ID or PID. Type the following command to restart kdm (Substituting the PID number you have for the 4530 in my example): Code: sudo kill -HUP 4530 2. SET THE VNC PASSWORD Type this in a terminal: Code: sudo vncpasswd /root/.vncpasswd 3. ADD VNC SERVICE TO XINETD Type this in a terminal: Code: sudo kate /etc/xinetd.d/Xvnc Enter this in to the new file: Code: 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 = 5901 } I recommend leaving all of that code alone, but you can safely change the 1024x768 to be a bigger or smaller resolution for your Xvnc window, depending on what you want. You can also change the depth, but understand that increasing the depth bits will cause more bandwidth to be used over your network, which could slow down your VNC experience considerably. 4. RESTART XINETD If the following code does not work, try rebooting: Code: sudo /etc/init.d/xinetd stop sudo killall Xvnc sudo /etc/init.d/xinetd start Don't worry if you see a message like "Xvnc: no process killed". This just means there was no open, active session of VNC running at the time. This is expected and is normal. 5. TEST If you followed all of the above steps correctly, you should now be able to test your VNC server. Type the following in a terminal: Code: vncviewer localhost:1 You should be prompted for the VNC password, and then see the KDM login screen where you can login and start a new X session. If that works, you can now go ahead and try to connect from remote machine using your favorite VNC client (remember to first close the local vncviewer we started above). Remember to use the VNC server machine's domain name or IP address, followed by :1 (e.g. 192.168.0.100:1). If connecting locally as shown above works, but connecting remotely fails, then this means you have a problem with a firewall which is blocking some ports. See the notes below about how to deal with that. Note about ports: The VNC server set up as shown uses TCP port 5901. If you are using firewall software (e.g. firestarter) on that machine, you need to allow incoming connections on this port. If you are using a router which assigns your machine a private address (e.g. 192.168.0.100) which is not accessible from the internet, then you need to forward TCP port 5901 from the router to this machine. Note about security: This setup allows any user to start an X-session remotely by logging in using his regular password (after starting the VNC connection using the VNC password), so if the user disconnects without logging out, any other user which knows the VNC password can connect afterwards and resume the same session that the first user started. So if you do not want to log out before disconnecting, it's advisable to at least lock your VNC X-session screen. Also note that while a remote user is connected thru VNC, no other connection will be accepted. An idle VNC client will be disconnected after one hour, but this can be changed by using the "-IdleTimeout" option in the server_args line in /etc/xinetd.d/Xvnc. For example, you can add "-IdleTimeout 300" to change it to 5 minutes. reference links: Gnome VNC howto: http://ubuntuforums.org/showthread.php?t=122402 Xdmcp in kdm: http://klomdark.servebeer.com:8081/M...px?MsgNum=1967 Good luck! Last edited by paperdiesel; September 29th, 2006 at 02:22 PM..

September 26th, 2006	#2
master_b A Carafe of Ubuntu Join Date: Aug 2005 Beans: 77	Re: HOWTO: Set up VNC server with resumable sessions - KUBUNTU VERSION Hi paperdiesel Thanks for the Kubuntu HowTo for vnc4server. I've been trying to get remote access (over my home LAN) to desktop:0 ( actual desktop) of a remote "headless" PC ie no monitor, mouse or keyboard, but its NVidea TV out is connected to a TV and I can view the "cloned" desktop ( and TV output) on that. Can successfully remotely access the pc using NX ( better than vnc, Krfb etc in my opinion) but none of those allow access to desktop:0, whereas vnc4 will ( at least according to its website). Will post re my success or otherwise. Bill

September 27th, 2006	#3
master_b A Carafe of Ubuntu Join Date: Aug 2005 Beans: 77	Re: HOWTO: Set up VNC server with resumable sessions - KUBUNTU VERSION Follow-up:- Worked perfectly except that I get a grey desktop. Remember having same problem eons ago with vnc but forget fix. Will figure it out and post. In addittion, NX still works without problems, whereas when I had plain vnc installed, NX wouldn't work when the vncserver was running. Bill

September 27th, 2006	#4
paperdiesel Way Too Much Ubuntu Join Date: Oct 2005 Beans: 243 Ubuntu 7.10 Gutsy Gibbon	Re: HOWTO: Set up VNC server with resumable sessions - KUBUNTU VERSION Hey Bill, If you want to use VNC to view display :0, I'd recommend x11vnc. I used it a while back, and if I remember correctly, it acts as a VNC extension to the X server, and loads inside your xorg.conf file and allows you to VNC in to the main display. I've also heard about people using vnc4server and getting grey screens. But if you're trying to use vnc4server to display :0, that might be why you're getting a grey screen. Try x11vnc and let me know if it works.

September 27th, 2006	#5
master_b A Carafe of Ubuntu Join Date: Aug 2005 Beans: 77	Re: HOWTO: Set up VNC server with resumable sessions - KUBUNTU VERSION Hi paperdiesel thanks for the reply. Have tried several "HowTos" for remote connecting to desktop:0, including x11vnc, but your instructions herewith are the only one's that I've found for Kubuntu. Problem is that many of the Ubuntu "Howtos" give instructions to use various Gnome Menu items that just don't exist with Kubuntu/KDE, and fail to name the actual config files that are altered. From past experience with vnc, which I haven't used since discovering NX, I have vague recollections that in order to fix the "grey screen" problem, a config file has to be altered to include the starting of the desired window manager, in this case kde. When I get time I'll dig through my old install notes and try to find the info. Have "googled" to no avail. I think that this "grey screen" problem can occur regardless of whether you are using Krdc, vnc, x11vnc etc. Bill

September 28th, 2006	#6
paperdiesel Way Too Much Ubuntu Join Date: Oct 2005 Beans: 243 Ubuntu 7.10 Gutsy Gibbon	Re: HOWTO: Set up VNC server with resumable sessions - KUBUNTU VERSION Ah, well if that's the case, the only config file I know that sounds similar to what you describe is the xstartup file, located in ~/.vnc/ Open up ~/.vnc/xstartup and scroll to the bottom of the file. If you see a line that looks like: Code: twm & Change it to: Code: startkde & . See if that helps.

December 24th, 2006	#7
glave A Carafe of Ubuntu Join Date: Jan 2006 Beans: 135	Re: HOWTO: Set up VNC server with resumable sessions - KUBUNTU VERSION Just for reference, I had a problem with myself getting a connection reset by peer. http://ubuntuforums.org/showthread.p...th#post1869576 Following the above advice (adding my fonts path to the config) I was able to get things working smoothly!

December 24th, 2006	#8
pickarooney Dipped in Ubuntu Join Date: Dec 2004 Beans: 568 Xubuntu 9.04 Jaunty Jackalope	Re: HOWTO: Set up VNC server with resumable sessions - KUBUNTU VERSION I get the following when running vncviewer localhost:1 on Kubuntu 6.10 64-bit, qfter forcing the dpkg files to install without deps. Code: VNC viewer for X version 4.0 - built Oct 19 2005 20:19:45 Copyright (C) 2002-2004 RealVNC Ltd. See http://www.realvnc.com for information on VNC. Mon Dec 25 00:51:54 2006 main: unable to connect to host: Connection refused (111) Same if I try to connect to 192.168.1.100 (my PC) or when changing the number after teh colon to 0 or 15900 (my open VNC port, set as such in the setup file).

December 25th, 2006	#9
leprasmurf First Cup of Ubuntu Join Date: Dec 2006 Beans: 10	Re: HOWTO: Set up VNC server with resumable sessions - KUBUNTU VERSION great guide, I'll have to try it with edubuntu.

April 15th, 2007	#10
deserthowler A Carafe of Ubuntu Join Date: Dec 2005 Beans: 112	Re: HOWTO: Set up VNC server with resumable sessions - KUBUNTU VERSION I am running Kubuntu Dapper. I had TightVNC installed so I uninstalled it and the other VNC stuff. I installed everything just as you said in the WIKI. It worked just as stated. I got the sign-in screen just as I wanted. I had the monitor running on the server computer and got a log-in window there too. I ended up running 2 sessions simultaneously ... one on the client and one on the server computer. I got a lot of error messages from kate so I went to nano and wrote the configuration files. GREAT WIKI!!!! It worked. That's all I can say. Earl Last edited by deserthowler; April 15th, 2007 at 01:38 AM.. Reason: more details: I am running on a PII 400 with 1 GB memory and an old S3 card. My client is a Sun U30 running Debian Etch.

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