topic Re: Problem with ssh in Operating System - HP-UX

Problem with ssh

marc seguin — Wed, 05 May 2004 09:39:30 GMT

I have openssh (v3.7.1p2) and openssl (v0.9.7c)
on my HP UX-11i.
I use PuTTY to connect to my HP server from my PC, with "X11 forwarding" enabled.

If I execute "xclock", i can see the clock window on my PC. But If i execute "xterm", i have the error message (on HP server) :
Xlib: connection to "localhost:10.0" refused by server
Xlib: Authentication failed at PuTTY X11 proxy
Error: Can't open display: localhost:10.0
Error: Couldn't find per display information

Please help...
thanks

Re: Problem with ssh

Bharat Katkar — Wed, 05 May 2004 11:24:36 GMT

Try doing this:
#xhosts + (on HP server)
#export DISPLAY=:0.0

then execute:
#xterm

Re: Problem with ssh

marc seguin — Wed, 05 May 2004 11:55:00 GMT

Dear Bharat,

DISPLAY is already well configured because it is possible to send a window to my PC (the xclock window). It looks like something to do with Xlib but I don't know anything about that.

Re: Problem with ssh

Lee Hundley — Wed, 05 May 2004 13:28:49 GMT

It could also have something to do with the X server on your PC. FWIW, I've seen instances where certain apps won't run because of an incomplete implementation on the PC's X Server. IE: "RENDER extension missing". Then again, I've no personal experience with PuTTY's X11 Forwarding.

Re: Problem with ssh

Mel Burslan — Wed, 05 May 2004 15:05:16 GMT

if you are running, on your pc, something like reflexion X, it is really strange that you see the xclock but not the xterm. But if you are running a little known x-server, like winaxe (which I unfortunately was using at one time in history) or some other home/usergroup brew xserver, see Lee Hundley's comment. Some xserver implementations are realyy halfbaked and good for nothing most of the time.

also, on the server side, are you really sure that the DISPLAY variable is set and your xterm command does not have a -d directive to specify the display as localhost. Because, from the error messages, it seems like your hpux server is trying to launch the xterminal on itself instead of your PC.

hth

Re: Problem with ssh

Dave Hutton — Wed, 05 May 2004 15:07:20 GMT

I found this doing a google search:

10.12 "Authentication failed at PuTTY X11 proxy"
This error is reported when PuTTY is doing X forwarding. It is sent back to the X application running on the SSH server, which will usually report the error to the user.

When PuTTY enables X forwarding (see section 3.4) it creates a virtual X display running on the SSH server. This display requires authentication to connect to it (this is how PuTTY prevents other users on your server machine from connecting through the PuTTY proxy to your real X display). PuTTY also sends the server the details it needs to enable clients to connect, and the server should put this mechanism in place automatically, so your X applications should just work.

A common reason why people see this message is because they used SSH to log in as one user (let's say "fred"), and then used the Unix su command to become another user (typically "root"). The original user, "fred", has access to the X authentication data provided by the SSH server, and can run X applications which are forwarded over the SSH connection. However, the second user ("root") does not automatically have the authentication data passed on to it, so attempting to run an X application as that user often fails with this error.

If this happens, it is not a problem with PuTTY. You need to arrange for your X authentication data to be passed from the user you logged in as to the user you used su to become. How you do this depends on your particular system; in fact many modern versions of su do it automatically.

It's part of the putty documention.

Re: Problem with ssh

marc seguin — Wed, 05 May 2004 15:30:56 GMT

Thanks to all, but it doesn't solve my problem.

Mel, yes I use Reflexion X. And the DISPLAY variable looks OK, because PuTTY sets it to the Server name, but with a different display number (see Dave's note).
And when I try to launch xterm, I do "xterm &". Is it possible that a "-d" option could be hidden ?

Dave, I know about the "su' problems. It can be solved with "xauth list" and "xauth add" commands. But for me, I don't change the user.

Note : It looks like only xterm has problems. I am able to get SAM and other graphic applications (Networker, Veritas Manager) on my PC display.

Re: Problem with ssh

marc seguin — Wed, 05 May 2004 15:39:43 GMT

Lee, I didn't forget what you said.
About my X server (Reflexion X) on my PC : I know that I can get an xterm window from another HP server.
I just tested it a few minutes ago.

So now i am going to compare the two configurations.

I'll let you know if I find something...

Re: Problem with ssh

Mel Burslan — Wed, 05 May 2004 18:39:49 GMT

It may be a hidden -d directive somewhere.
you said there is a system which can display on to this reflexion X running windows workstation, which eliminates the misconfiguration of the x server on the PC

while the successful terminal displaying on your screen, do a ps -ef | grep xterm and at the same time run the same command in an endless loop, capturing output to a file while you try starting up the xterm from the system with failures. Exemplifying:

sys1 : where it runs and displays fine
sys2 : where it errors out

on sys1:
export DISPLAY=a.b.c.d:0.0
xterm
ps -ef | grep xterm (after the xterminal displays on your workstation)

on sys2:
create file logger.sh

#file: logger.sh
while true
do
ps -ef | grep xterm >> /tmp/dump
done

chmod 700 logger.sh
export DISPLAY=a.b.c.d:0.0
./logger.sh &
xterm
(wait until it errors out)
kill %1 (assuming this is the first job running in the background)

at this point examine the /tmp/dump file to see if the command is running with a -d directive, i.e, instead of accessing the xterm binary, you may be running a script called xterm which may in turn be running the actual xterm binary with a -d option.

also, you can try to invoke xterm using its full path name.

if all of these did not give you anything different, assuming OS versions of sys1 and sys2 are equal, I would suggest copying the xterm binary from sys1 to sys2:/tmp/xterm

then try to run xterm by invoking command /tmp/xterm. if this runs okay, you may probably rule that you had a corrupt binary.

good luck.

Re: Problem with ssh

Matti_Kurkela — Thu, 06 May 2004 08:30:06 GMT

Set "X11UseLocalhost" to "no" in sshd_config file and restart sshd.

For some reason, HP ships both "older" and "newer" style X applications in HP-UX. The newer ones can handle "localhost" in $DISPLAY variable, but the older ones can't.

Re: Problem with ssh

marc seguin — Tue, 11 May 2004 10:59:13 GMT

Yes Matti you got it. I found by myself before reading your post.
I noticed that xterm is linked to X11R5 libs. And my other applications are linked to X11R6 libs.
It seems that X11R5 cannot deal with the DISPLAY var set to localhost:x.x, but it needs to be like :x.x
When changing the settings for ssh, it works, but it is a bit less secure.

(Perhaps you explain that in the file attached, but I can't read it.)

Now the question is :
Is there a xterm using X11R6 libs ?

Marc.

Re: Problem with ssh

marc seguin — Tue, 11 May 2004 11:56:32 GMT

I found it in /usr/contrib/bin/X11 !!