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X11 Forwarding

It drives me crazy.... I cannot establish this X11-Forwarding.

I have a Debian Linux Kernel 2.4 with OpenSSH I enabled X11Forwarding in the
sshd_config. I have no script that overwrites the DISPLAY var, but when I
use putty on my WinXP-Client and forward X11 from my client, it does not set
the DISPLAY variable on the server. Even if tell server afterwards: "export
DISPLAY=localhost:10.0" (display 10 ist configured in the sshd_conf), all
X-Applications tell me, that they can't connect to the display. I have tried
everything I found on the net. I even played around with such parameters
like UseLogin (if that one is set to yes it disable X11-Forwarding).

Please don't write me such a crap like DISPLAY must be the client:0.0 or
something. I want to tunnel the X11-Session through SSH. I often heard this
suggestion, but that is not a secure way.

--
Best regards and thx for help
basser, Germany
ICQ #92027975


0
6/30/2003 11:44:02 PM
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"Manuel 'basser' Muehlig" <manuel.muehlig@stud.tu-ilmenau.de> wrote:
> It drives me crazy.... I cannot establish this X11-Forwarding.

> I have a Debian Linux Kernel 2.4 with OpenSSH I enabled X11Forwarding in the
> sshd_config. I have no script that overwrites the DISPLAY var, but when I
> use putty on my WinXP-Client and forward X11 from my client, it does not set
> the DISPLAY variable on the server.

Did you tell PuTTY to forward X ?  It's the "Enable X11 Forwarding"
option under Connection/SSH/Tunnels.

Also, I assume you have an X server on your Windows box?  Like Exceed
or the Cygwin Xwin ?

0
pa9518 (1)
7/1/2003 12:13:29 AM
Not sure whats wrong put a couple of things to try:

i) try X tunneling on localhost (server) only, ie. cut out the win 
client. Something like ssh -X localhost

ii) start an sshd2 daemon on another port with debug on (-d) to see what 
happens and also connect with -v on the client.

iii) Did you compile ssh ? If so did it find the X libs?

hth,
chesh.

Manuel 'basser' M�hlig wrote:
> It drives me crazy.... I cannot establish this X11-Forwarding.
> 
> I have a Debian Linux Kernel 2.4 with OpenSSH I enabled X11Forwarding in the
> sshd_config. I have no script that overwrites the DISPLAY var, but when I
> use putty on my WinXP-Client and forward X11 from my client, it does not set
> the DISPLAY variable on the server. Even if tell server afterwards: "export
> DISPLAY=localhost:10.0" (display 10 ist configured in the sshd_conf), all
> X-Applications tell me, that they can't connect to the display. I have tried
> everything I found on the net. I even played around with such parameters
> like UseLogin (if that one is set to yes it disable X11-Forwarding).
> 
> Please don't write me such a crap like DISPLAY must be the client:0.0 or
> something. I want to tunnel the X11-Session through SSH. I often heard this
> suggestion, but that is not a secure way.
> 
> --
> Best regards and thx for help
> basser, Germany
> ICQ #92027975
> 
> 

0
ncheshire (1)
7/1/2003 9:39:43 AM
may be you need to tell your x-server that he should accept connections
from the debian box.
on a linux box you do that like this:

xhost +name-of-the-debian-box

or

xhost +name-of-the-user-that-is-allowed-to-connect

or 

xhost +

the last command is to accept all connections to the x-server from
everyone.

remember to disable the access after you are connected.

if that doesn't work login to your debian box via ssh and look what the
command:

echo $DISPLAY

returns.

hth
christian



On Tue, 01 Jul 2003 08:45:47 +0200, Manuel 'basser' M�hlig wrote:

>> Did you tell PuTTY to forward X ?  It's the "Enable X11 Forwarding"
>> option under Connection/SSH/Tunnels.
> Oh yes of course I have set putty up to forward the display 0 from the
> client. I also trie it with secure shell ssh client but there is now
> difference.
> 
>> Also, I assume you have an X server on your Windows box?  Like Exceed
>> or the Cygwin Xwin ?
> I have installed Cygwin and I start the GUI with command "startx" before
> I establish the connection to the server.
> 
> --
> basser, Germany
> ICQ #92027975
0
7/2/2003 9:51:56 AM
>>>>> "MM" == EmptyMM  <emptymm@cox.net> writes:

    MM> I know this is an obvious one but is the "client" machine
    MM> firewalled? If so, try it turned off/DMZ'd..

This is irrelevant; the point is to be using SSH X forwarding, which would
bypass such a firewall.  The SSH client need only be able to access the X
server running on the same host.

    >> It drives me crazy.... I cannot establish this X11-Forwarding.  I
    >> have a Debian Linux Kernel 2.4 with OpenSSH I enabled X11Forwarding
    >> in the sshd_config. I have no script that overwrites the DISPLAY
    >> var, but when I use putty on my WinXP-Client and forward X11 from
    >> my client, it does not set the DISPLAY variable on the server.

This means that for whatever reason, the SSH connection is not setting up
X forwarding.

    >> Even if tell server afterwards: "export DISPLAY=localhost:10.0"
    >> (display 10 ist configured in the sshd_conf), all X-Applications
    >> tell me, that they can't connect to the display.

Of course not.  If X forwarding were set up, then the server would have
set the DISPLAY for you.  If it's not, then setting itself will not help,
because there's no proxy X display there to connect to.

Follow the directions at:

  http://www.snailbook.com/faq/general-debugging.auto.html

to isolate the problem.  Note that the local DISPLAY variable must usually
be set before an SSH client will do X forwarding, since it must have
access to the X display.

-- 
  Richard Silverman
  res@qoxp.net

0
res49 (1410)
7/3/2003 1:56:35 PM
Manuel 'basser' M�hlig sez:
>> Did you tell PuTTY to forward X ?  It's the "Enable X11 Forwarding"
>> option under Connection/SSH/Tunnels.
> Oh yes of course I have set putty up to forward the display 0 from the
> client. I also trie it with secure shell ssh client but there is now
> difference.
> 
>> Also, I assume you have an X server on your Windows box?  Like Exceed
>> or the Cygwin Xwin ?
> I have installed Cygwin and I start the GUI with command "startx" before I
> establish the connection to the server.

Since you already have Cygwin, install their OpenSSH and
try forwarding with that.

Dima
-- 
One distinguishing characteristic of BOFHen is attention deficit disorder.
Put me in front of something boring and I can find a near-infinite number
of really creative ways to bugger off.                                   -- ADB
0
Dimitri
7/5/2003 1:31:03 AM
Reply: