HOWTO: x11vnc (vnc for display :0)

[ErikTheRed]

x11vnc is very similar to vnc, except that it allows you to view display :0, the display that would currently be showing on your monitor if you were sitting at your computer.

1. Install the package

sudo aptitude install x11vnc

2. Run the following command

ps wwaux | grep auth

This command should output something like this:

root 3838 10.1 1.7 13308 8840 tty7 Ss+ 15:35 2:14 /usr/bin/X -br -nolisten tcp :0 vt7 -auth /var/run/xauth/A:0-LliKdB
erik 5156 0.0 0.1 2800 752 pts/0 R+ 15:57 0:00 grep auth

Note the bolded path after -auth, as you will need this for the next step

3. Add x11vnc service to xinetd

sudo nano /etc/xinetd.d/x11vnc


Enter this into the new file:

service x11vnc
{
port = 5900
type = UNLISTED
socket_type = stream
protocol = tcp
wait = no
user = root
server = /usr/bin/x11vnc
server_args = -inetd -o /var/log/x11vnc.log -display :0 -auth /var/run/xauth/A:0-LliKdB -many -bg
disable = no
}
Notice the bolded path, this is where you put the path you found in step 2.

4. Restart xinetd

sudo /etc/init.d/xinetd restart

5. You can now connect to display :0 from another machine by using a VNC client. For example:

sudo vncviewer vnchost:0

A lot of this is thanks to Tichondrius' great VNC HOW-TO which is here (http://ubuntuforums.org/showthread.php?p=771174). His post on using x11vnc (http://ubuntuforums.org/showpost.php?p=771174&postcount=61) is on page 7 of that thread. In his HOW-TO there was an issue where the connection would drop out whenever you logged in or out, but I believe I have rectified this problem by using the new method to find the path to use with the -auth option.

Please let me know if there are any problems with this HOW-TO.

[krunge]

Hi,

Newer versions of x11vnc (might not be in ubuntu yet) support automatic
finding of the -auth authority file, and can also find both the DISPLAY and authority
file using unix username and password login. This is the FINDDISPLAY
stuff here: http://www.karlrunge.com/x11vnc/faq.html#faq-userlogin

E.g.:


server_args = -inetd -o /var/log/x11vnc.log -svc

or -xdmsvc instead of -svc. The -find option may also be useful here.

[benfindlay]

I have been trying to get this set up, but when I type
ps wwaux | grep auth to find the code for the -auth part, it just says
-auth /var/lib/gdm/:0.Xauth

Am I going wrong anywhere obvious?

Cheers

[benfindlay]

Just realised I have only been trying to connect via SSH. Just tried it and it will connect direct, but not through SSH. Any ideas why that is then?

[krunge]

Am I going wrong anywhere obvious?

No, that looks fine. /var/lib/gdm/:0.Xauth is where gdm(1) puts the server auth file. It's nice that the filename doesn't have a random part like the kdm and xdm servers do. Please send your entire /etc/xinetd.d/x11vnc (or equivalent) file.


Just realised I have only been trying to connect via SSH. Just tried it and it will connect direct, but not through SSH. Any ideas why that is then?


What was the full ssh command you ran, and the vncviewer command you ran? Do any errors or warnings get printed out (either by ssh, vncviewer, or in the x11vnc log file)?

[Al_maverick]

When xinetd starts I get an error in daemon.log. Any idea what it may be?



Mar 14 21:57:06 maverick xinetd[11740]: Reading included configuration file: /etc/xinetd.d/chargen [file=/etc/xinetd.conf] [line=14]
Mar 14 21:57:06 maverick xinetd[11740]: Reading included configuration file: /etc/xinetd.d/daytime [file=/etc/xinetd.d/daytime] [line=28]
Mar 14 21:57:06 maverick xinetd[11740]: Reading included configuration file: /etc/xinetd.d/discard [file=/etc/xinetd.d/discard] [line=26]
Mar 14 21:57:06 maverick xinetd[11740]: Reading included configuration file: /etc/xinetd.d/echo [file=/etc/xinetd.d/echo] [line=25]
Mar 14 21:57:06 maverick xinetd[11740]: Reading included configuration file: /etc/xinetd.d/time [file=/etc/xinetd.d/time] [line=26]
Mar 14 21:57:06 maverick xinetd[11740]: Reading included configuration file: /etc/xinetd.d/x11vnc [file=/etc/xinetd.d/x11vnc] [line=28]
Mar 14 21:57:06 maverick xinetd[11740]: removing chargen
Mar 14 21:57:06 maverick xinetd[11740]: removing chargen
Mar 14 21:57:06 maverick xinetd[11740]: removing daytime
Mar 14 21:57:06 maverick xinetd[11740]: removing daytime
Mar 14 21:57:06 maverick xinetd[11740]: removing discard
Mar 14 21:57:06 maverick xinetd[11740]: removing discard
Mar 14 21:57:06 maverick xinetd[11740]: removing echo
Mar 14 21:57:06 maverick xinetd[11740]: removing echo
Mar 14 21:57:06 maverick xinetd[11740]: removing time
Mar 14 21:57:06 maverick xinetd[11740]: removing time
Mar 14 21:57:06 maverick xinetd[11740]: bind failed (Address already in use (errno = 98)). service = x11vnc
Mar 14 21:57:06 maverick xinetd[11740]: Service x11vnc failed to start and is deactivated.
Mar 14 21:57:06 maverick xinetd[11740]: xinetd Version 2.3.14 started with libwrap loadavg options compiled in.
Mar 14 21:57:06 maverick xinetd[11740]: Started working: 0 available services

[jpkotta]

This is what I use to connect to an already running server (on display :0):

#!/bin/bash

usage="$0 [user@]remote_host"

if [[ x$1 == x"" ]] ; then
echo $usage
exit 1
fi

ssh $1 'x11vnc -localhost -display :0 -scale 4/5 -bg'
vncviewer -via $1 -encodings 'copyrect tight zrle hextile' localhost:0


All you need is X11Forwarding in ssh.

[krunge]

Mar 14 21:57:06 maverick xinetd[11740]: bind failed (Address already in use (errno = 9 ). service = x11vnc

It looks like something else is already listening on port 5900.

Check 'netstat -ant | grep 5900' output and (perhaps as root) 'lsof -P | grep 5900'

[Al_maverick]

It looks like something else is already listening on port 5900.

Check 'netstat -ant | grep 5900' output and (perhaps as root) 'lsof -P | grep 5900'

That was it. I dunno why, krfb was still running. I killed it, then inmediately afterwards I restarted xinetd. Now it worked. Thanks a lot!

[FlashUK]

Very useful thread. Been following the steps to get x11vnc working on edgy 6.10 ubuntu.
Managed to get it to work on the end on port 5900 but I'd like to point out a mistake on the karlrunge.com that had me scrathing my head for ages:


x11vnc -display :0 -auth /var/gdm/:0.Xauth

Please note that ubuntu's gdm is located at /var/lib/gdm/:0.Xauth. I missed out the word lib when I was writing my xinetd file.
But now it even works on bootup! Thanks very much for sharing this with us :)

Btw, edgy currently uses 0.8.2 of x11vnc.

[Jbloudg20]

Any reports if this will work for a dual head configuration using FGLRX drivers? I am using the default VINO right now, and we all know how buggy that is.

[Ek0nomik]

Thanks ErikTheRed. Worked on the first try. :)

I am using a Radeon 9800 using fglrx drivers in case anyone is wondering.

Cheers!

[Jbloudg20]

I dont seem to have a /etc/xinetd directory. When I go to create the file as specified, it won't let me saying the directory does not exist. sure enough ls /etc shows there is not xinetd directory.

I am trying to get this running! Can anyone help?

[krunge]

You probably have a /etc/inetd.conf based inetd.

Here is how I do these this sort of thing on those systems. Add a single line to that file like this:


5900 stream tcp nowait root /usr/sbin/tcpd /usr/local/bin/x11vnc.sh

where, for simplicity, I just put the x11vnc call and its option in the shell script /usr/local/bin/x11vnc.sh

Then something like: /etc/init.d/inetd restart
to restart inetd, and of course if your system filrewall blocks port 5900 you will have to poke a hole in it.

More info: http://www.karlrunge.com/x11vnc/faq.html#faq-inetd

[Jbloudg20]

I don't have that file either. Should I?

[krunge]

I don't have that file either. Should I?

If you want to run inetd (you can find manpages and other documention for it on the web) you will need to install some package probably named "inetd" or "xinetd".

In 24 years of using unix I've never seen a machine w/o inetd (except perhaps for some locked down boxes where it was forcibly removed after install), but I guess there is a first time for everything ;-)

[Jbloudg20]

Well, I really don't want to go through a thousand hoops to make this work. VINO works right now, albeit very buggy.

I had kind of thought this would be a fairly simple, install a package, start a service at startup thing. Guess not.

[krunge]

I had kind of thought this would be a fairly simple, install a package, start a service at startup thing. Guess not.

No, it's pretty easy. You don't need inetd stuff like the people in this thread are talking about.

You just need to install the x11vnc package (see the beginning of this thread or http://www.karlrunge.com/x11vnc/bins) and
type "x11vnc" in a window or if you ssh in remotely type "x11vnc -display :0" to point it
at the X session display you are logged into.

At that point it is the same service as vino. If you want it to always be available put it in your gnome or kde "Startup Programs". You should give it the "-forever" option to keep listening after the first client disconnects.

[bdogg64]

x11vnc is very similar to vnc, except that it allows you to view display :0, the display that would currently be showing on your monitor if you were sitting at your computer.

1. Install the package

sudo aptitude install x11vnc

2. Run the following command

ps wwaux | grep auth

This command should output something like this:

root 3838 10.1 1.7 13308 8840 tty7 Ss+ 15:35 2:14 /usr/bin/X -br -nolisten tcp :0 vt7 -auth /var/run/xauth/A:0-LliKdB
erik 5156 0.0 0.1 2800 752 pts/0 R+ 15:57 0:00 grep auth

Note the bolded path after -auth, as you will need this for the next step

3. Add x11vnc service to xinetd

sudo nano /etc/xinetd.d/x11vnc


Enter this into the new file:

service x11vnc
{
port = 5900
type = UNLISTED
socket_type = stream
protocol = tcp
wait = no
user = root
server = /usr/bin/x11vnc
server_args = -inetd -o /var/log/x11vnc.log -display :0 -auth /var/run/xauth/A:0-LliKdB -many -bg
disable = no
}
Notice the bolded path, this is where you put the path you found in step 2.

4. Restart xinetd

sudo /etc/init.d/xinetd restart

5. You can now connect to display :0 from another machine by using a VNC client. For example:

sudo vncviewer vnchost:0

A lot of this is thanks to Tichondrius' great VNC HOW-TO which is here (http://ubuntuforums.org/showthread.php?p=771174). His post on using x11vnc (http://ubuntuforums.org/showpost.php?p=771174&postcount=61) is on page 7 of that thread. In his HOW-TO there was an issue where the connection would drop out whenever you logged in or out, but I believe I have rectified this problem by using the new method to find the path to use with the -auth option.

Please let me know if there are any problems with this HOW-TO.

This is a great HOWTO, but there is one part missing to get it completely working in KDE.


ps wwaux | grep auth

will return a different file every time you reboot, unless you add the setting in /etc/kde3/kdm/kdmrc under [X-:*-Core]


AuthFile=A:0-LliKdB

You can change the AuthFile to be something different, just make sure you have the same file in your server_args in your Xvnc services file

I hope this helps someone

B

[Gujs]

Is there a way to automatically lock gnome session when I exit vncviewer? Because I don't want to have accessible session if somebody comes to my computer.

[krunge]

Is there a way to automatically lock gnome session when I exit vncviewer? Because I don't want to have accessible session if somebody comes to my computer.

For x11vnc see this link: http://www.karlrunge.com/x11vnc/faq.html#faq-gone-lock For example, you supply:


x11vnc ... -gone "xlock -mode blank &"

or whatever command invokes a screen locker.

[jnorth]

@ErikTheRed - cool guide - but just curious, why run using xinetd?

The method I've been using for some time is detailed here and IMHO *might* be a little easier?

Anyway, I'm not posting this to take away from your thread, I just merely do not want to duplicate Howto's, especially if there's a reason not to do this using gdm as I have been.

Here's the link to another post I created for a user asking questions:
http://ubuntuforums.org/showpost.php?p=2757451&postcount=6

Thanks - no offense, just hoping to add to the community ;)

[4integration]

This is a great HOWTO, but there is one part missing to get it completely working in KDE.


ps wwaux | grep auth

will return a different file every time you reboot, unless you add the setting in /etc/kde3/kdm/kdmrc under [X-:*-Core]


AuthFile=A:0-LliKdB

You can change the AuthFile to be something different, just make sure you have the same file in your server_args in your Xvnc services file

I hope this helps someone

B

I am trying to get x11vnc to run under Kubuntu Feisty Fawn but having problems.
By setting the AuthFile to A:0-test1 it's created in file system root (/) not in /var/run/xauth/.
I have also tried absolute path in AuthFile and also to set AuthDir to /var/run/xauth and then I don't find the file at all.

If you have some ideas I would be happy.

[maybeway36]

I always set the AuthFile to /root/xauth and use that path in the x11vnc arguments.

[krunge]

I always set the AuthFile to /root/xauth and use that path in the x11vnc arguments.

That's smart. I wish the default system configuration was that clever.

[Deadmode]

if you are getting vnc to work, but you want it password protected be sure to add -passwd "yourpassword" into the server arguments.


service x11vnc
{
port = 5900
type = UNLISTED
socket_type = stream
protocol = tcp
wait = no
user = root
server = /usr/bin/x11vnc
server_args = -inetd -o /var/log/x11vnc.log -display :0 -auth /var/lib/gdm/:0.Xauth -passwd yourpassword -many -bg
disable = no
}

then I would set that file to root.

sudo chmod 600 /etc/xinetd.d/x11vnc

Now when you vnc into your computer it will prompt you with a password and also if anyone was tampering with your computer they wouldn't be able to mess with or see your password for /etc/xinetd.d/x11vnc file.