here is help I recieved with this
Ken
Ken,
I think that I have found the problem with your display. When you logged in
as root you lost the authorization for the display. The long version can be
found on this page...
https://www6.software.ibm.com/developerworks/education/l-lpic1110/section4.html
You need to log in though. So here is an excerpt from that page.
Good luck
cheers
----
Exporting a display
An X display is known by a name of the form
hostname:displaynumber.screennumber. For Linux running on a workstation such
as a PC, there is typically only one display with a single screen. In this
case, the displayname may be, and usually is, omitted so the display is
known as :0.0. The DISPLAY environment variable is usually set to the
display name., so you can display it using the command echo $DISPLAY.
Depending on your system, this variable may or may not be set if you use
su - to switch to another user. In such a case, you may need to set and
export the DISPLAY as shown in Listing 25. In this listing you see an
attempt to start the xclock application after switching to root, but the
attempt fails because the DISPLAY environment variable is not set. Even if
the DISPLAY variable is set, you still may not be able to use the display,
as you will also need authorization to do so.
Listing 25. Attempting to start xclock
[EMAIL PROTECTED]:~> whoami
ian
[EMAIL PROTECTED]:~> echo $DISPLAY
:0.0
[EMAIL PROTECTED]:~> su -
Password:
lyrebird:~ # echo $DISPLAY
lyrebird:~ # xclock
Error: Can't open display:
lyrebird:~ # export DISPLAY=:0.0
lyrebird:~ # echo $DISPLAY
:0.0
lyrebird:~ # xclock
Xlib: connection to ":0.0" refused by server
Xlib: No protocol specified
Error: Can't open display: :0.0
lyrebird:~ # export XAUTHORITY=~ian/.Xauthority
lyrebird:~ # xclock
lyrebird:~ # ls -l ~ian/.Xauthority
-rw------- 1 ian users 206 Feb 18 16:20 /home/ian/.Xauthority
Let's take a look at what is going on here. In this case, the user ian
logged in to the system and his DISPLAY environment was set to :0.0 as we
expect. When user ian switched to user root, the DISPLAY environment
variable was not set, and an attempt to start xclock failed because the
application did not know what display to use.
So the substituted user, root, set the DISPLAY environment variable, and
exported it so that it would be available to other shells that might be
started from this terminal window. Note that setting and exporting an
environment variable does not use the leading $ sign, while displaying or
otherwise using the value does. Note too, that if the su command had omitted
the - (minus) sign, the DISPLAY environment variable would have been set as
it had been for user ian. Nevertheless, even with the environment variable
set, xclock still failed.
The reason for the second failure lies in the client/server nature of X.
Although root is running in a window on the one and only display on this
system, the display is actually owned by the user who logged in originally,
ian in this case. Let's take a look at X authorization.
Alan L Tyree wrote:
On Sun, 28 Jan 2007 18:42:00 +1100
Sam Lawrance <[EMAIL PROTECTED]> wrote:
On 28/01/2007, at 5:27 PM, Alan L Tyree wrote:
On Sun, 28 Jan 2007 16:54:52 +1100
Sam Lawrance <[EMAIL PROTECTED]> wrote:
On 28/01/2007, at 4:44 PM, Alan L Tyree wrote:
I have been trying to install x11vnc and then use ssh tunnels to
connect. There are two different machines that I am trying to
connect to, one Ubuntu and one is an Apple iBook running Xubuntu.
1 I have no problem with either machine NOT using ssh
2 using ssh: ssh -L 5900:localhost:5900 remote_name 'x11vnc
-localhost -display :0'
Works great with the Ubuntu machine
Does not work with the Xubuntu machine (vncviewer
localhost:0 appears to connect, but there is no display)
I presume it must be some setting in ssh, but I can't see any
difference.
Can anyone help?
Try using the verbose flag to ssh and/or x11vnc, and compare the
two machines.
Hmm. I can't do a simple X forwarding to the Xubuntu machine.
[EMAIL PROTECTED]:~$ ssh -v -X misty emacs
...
emacs: standard input is not a tty
I think the original problem lies elsewhere - that's an expected
error, see the SSH manpage regarding tty / pty allocation and the -t
option.
It fails with all programs.
The problem is that the DISPLAY variable is not getting set. After
logging into both machines with ssh -X machine_name
-----------------------------
[EMAIL PROTECTED]:~$ echo $DISPLAY
localhost:10.0 ** Ubuntu machine where everything works
-----------------------------
[EMAIL PROTECTED]:~$ echo $DISPLAY
** Xubuntu machine where nothing works
[EMAIL PROTECTED]:~$
------------------------------
The /etc/ssh/sshd_config files are the same in both machines.
I don't know how DISPLAY gets set
--
SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/
Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
