cannot open display localhost:10.0 - Solved Yet?

[miguel]

Hi,

I've seen a few posts on this with no apparent resolution.

I can connect to my remote host (slackware 12.2), login, then run
say...xterm. Aproximately 1 time in ten it is successful and I switch
to the root X window and see xterm running. The rest of the time, I
get cannot open display localhost:10.0. I monitor the logs on the
remote host as I attempt to run X progs and see nothing out of the
ordinary. I would really like to see a resolution to this issue.

Thanks
M

[Michael Martin]

I can imagine that is rather aggravating. For what it is worth, this works fine for me over my local LAN and my Macs (FreeBSD). (I realize that is not a solution for your problem).

On Jul 25, 2010, at 4:18 PM, miguel wrote:

> I can connect to my remote host (slackware 12.2), login, then run
> say...xterm. Aproximately 1 time in ten it is successful and I switch
> to the root X window and see xterm running. The rest of the time, I
> get cannot open display localhost:10.0. I monitor the logs on the
> remote host as I attempt to run X progs and see nothing out of the
> ordinary. I would really like to see a resolution to this issue.

==================================================================
Michael Martin
ArsAstr...@gmail.com
==================================================================

[Wayne Brehob]

Miguel,

Have you confirmed that your display is set by SSH, and you are not
hard-coding "localhost:10.0" somewhere? SSH may use other displays (:
11.0, :15.0, whatever) depending on what ports are in use. Just
checking for one possible explanation of the failures that would not
require an iSSH fix...

Wayne

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[miguel]

Thanks for the replies.

I can confirm that it is SSH setting the display variable.

If I login to the slackware box from a PC using putty or cygwin or
from another linux box, and echo $DISPLAY...it is not set.

If I use putty with X11 forwarding enabled and login and then echo
$DISPLAY...localhost:10.0

If I have an X server running on the PC (XMing) and then login to the
slackware box using putty with X11 forwarding enabled...I can run any
X program just fine.

So...I'm not sure where to go next.

M

[Chris Jones]

Hi

I think I would flip the sshd's LogLevel to DEBUG and see if it produces any clues.

Chris Jones

[mick crane]

On Tue, July 27, 2010 1:04 am, miguel wrote:

> If I have an X server running on the PC (XMing) and then login to the
> slackware box using putty with X11 forwarding enabled...I can run any X
> program just fine.
>
> So...I'm not sure where to go next.
>

I just do the above and everything seems to work.
cheese(webcam), firefox

over issh sometimes it works (cheese) firefox hasn't worked yet.
I'm using dyndns to get at my router.

mick

[Dean]

Sorry for my late reply to this thread. I can't imagine anything in
my experience that would allow for X11 forwarding for one system but
not the other. To me this sounds like some white list or special
authentication method is being used. Under all the "stock" distro
installs I test with (Ubuntu, Fedora, CentOS) the X11 forwarding works
automatically. This doesn't mean you're not having problems or it's
exceptionally rare, but rather I've yet to have been able to replicate
it on my end of things.

Dean

[PTMixer]

Hello:

'Me too'.

I am likely less knowledgeable than the OP, but I'm getting the same
error. My setup:

iSSH 4.3.2 on my iPad
Make a Shell connection over SSH to an Ubuntu 10.04.1 LTS Server
installation (VM running in ESXi) that I recently installed Xfce
desktop packages on (GUI works fine on local console). I get text
login prompt as expected.
If I type startxfce4 I get this error: "/usr/bin/startxfce4: X server
already running on display localhost:10.0" and a bunch of other errors
also follow.

At first I thought this was because the machine booted to a GUI login
prompt, so I managed to get Ubuntu to just boot up to a text login
prompt by changing a setting in Grub2.

If I type xterm at the shell prompt (in iSSH) I get some different
errors; libxfcegui4-warning ICE I/O Error, then "disconnected from
session manager".

I chose Xfce because I thought it would run a little better than Gnome
with limited resources. Can you recommend a method for users (who are
perhaps new to X forwarding) to experience an X session on the iPad --
I certainly could have missed a critical setting in Ubuntu to make it
work. Basically I want to have the full desktop draw on the iPad with
iSSH as the window server. Is that possible?

Thanks.

[Dean]

PTMixer,

Your error is different than the original poster's. The error message
given by "startxfce4" is the clue. It says, "X server already running
on display localhost:10.0". This means the connection has already
been made and the system is aware of the remote X server. What seems
to be going on here is some scripting in the background that tries to
start up an X server if it doesn't see on running locally.

Dean

[HaJo]

Hmm, may have sent this to miguel rather than the group... Apologies
if so. Anyway:

On Jul 26, 6:18 am, miguel <michael.deng...@gmail.com> wrote:
> The rest of the time, I
> get cannot open display localhost:10.0.

Same here. I can positively confirm that when I log in to the target
server from another Linux box (ssh -X), then sshd on the server sets
$DISPLAY to localhost:10.0 and X11 forwarding works.

When logging in to the server with iSSH 4.3.2, iOS 4.0.1, from the
same subnet as the Linux box, $DISPLAY gets set to localhost:10.0 as
well, but X fails with "can not open display". This has worked
reliably before with earlier versions of iSSH, but by on iOS3. So my
guess is that either an iSSH update or iOS4 broke things (for me at
least). If I could take another guess, I'd suspect that either iSSH
doesn't keep the tunnel (properly) open or the iSSH X-Server doesn't
terminate the tunnel properly.

[Gary Au]

will the problem to be solved in next release ? SSH for tunnel for X
server is much better then VNC because screen resolution of remote
server can be tune to fit ipad size ...

[Michael Martin]

Odd, It works fine for me. iOS 4.01/iPhone 4, Mac OSX 10.6.4.

On Jul 31, 2010, at 11:52 PM, HaJo wrote:

> earlier versions of iSSH, but by on iOS3. So my
> guess is that either an iSSH update or iOS4 broke things (for me at
> least)

[Dean]

Unfortunately, I have yet been unable to replicate a failure to tunnel
an X11 connection. I presently test with OS X 10.6.4, Fedora 13,
Ubuntu 10.04 and CentOS 5.

To assist in replicating this condition, for those having problems,
please clearly specify the device (iPhone or iPad) and the distro/
version you're trying to connect to.

Also, something some of you may want to try is setting X11UseLocalhost
to "yes" in your /etc/ssh/sshd_config file (restart sshd of course!)

Dean

[HaJo]

On Aug 2, 5:22 am, Dean <canada...@gmail.com> wrote:

> Also, something some of you may want to try is setting X11UseLocalhost
> to "yes" in your /etc/ssh/sshd_config file (restart sshd of course!)

Tried, no effect. Shouldn't be anyhow, since it's by default commented
out and defaults to yes anyhow.

I do have debug-logs of sshd (Opensshd 4.3p2) on an up2date Centos 5.5
available, both coming from a up2date Fedora 12 (OpenSSH 5.3p1) and
from iSSH 4.3.2 on iOS4.0.1 on iPhone 3GS. Both through Wifi from the
same subnet (but I also tried from a FQDN IP through 3G, no
difference). The logs show a difference in how the X11 forwarding is
established, but to my limited knowledge no show-stoppers. If someone
wants the logs, I can send through private mail (don't really like to
post sshd logs publicly...). Just let me know.