Remote X applications (Re: [Techtalk] Re: Discovering my IP address)

[Sue Stones]

On Mon, 15 Mar 2004 06:08 pm, John Clarke wrote:
> On Mon, Mar 15, 2004 at 05:41:52PM +1100, Sue Stones wrote:
> > On Mon, 15 Mar 2004 04:33 pm, John Clarke wrote:
> > > If sshd is running on the remote server and supports password
> > > authentication, simply running:
> > >
> > >     ssh remote_user at remote_host
> > >
> > > should ask you for your password and give you a remote shell.  You may
> > > need to add '-X' to enable X11 forwarding.
> >
> > How wonderfully easy.  But it still doesn't open the windows that I need,
> > (with or without -X).
>
> Can you connect to the remote host with ssh?

Yes I can connect. 

> Do you get any error or warning messages when you connect?

I don't get any error messages at all.  But when I am in Matlab and I type a 
comand that requires it to open a window ... nothing happens ... at all.

> What's the value of $DISPLAY on the remote host?  I'd expect it to be
> something like localhost:10.

$DISPLAY is indefined for mu user account.
(I have an ordinary user account on the remote host.)

> Is there something listening on port 6010 of the remote host?
>
> Are you trying to run Matlab on the same machine that you've logged in
> to with ssh?

Yes the same machine.  
<snip>
> To get this far requires that X11 forwarding be enabled in the sshd
> config file on the remote server, in this example, my home machine:

It loks a lot like this may be the problem.

>     [root at dropbear ~]# grep X11 /etc/ssh/sshd_config
>     # X11
>     X11Forwarding yes
>     X11DisplayOffset 10
>
> If it's not enabled, X11 forwarding is blocked without any warning or
> error message when I connect.  Also, $DISPLAY remains unset and there's
> nothing listening on port 6010.  This is what that session looks like:
>
>     [johnc at dropbear ~/tmp]$ ssh -X dropbear.kirriwa.net
>     Last login: Mon Mar 15 17:52:38 2004 from wombat.vastsystems.com.au
>     [johnc at dropbear ~]$ echo $DISPLAY
>
>     [johnc at dropbear ~]$ netstat -atn|grep 6010
>     [johnc at dropbear ~]$ xterm &
>     xterm Xt error: Can't open display:
>
>
> Cheers,
>
> John

csusap.csu.edu.au% which matlab
/local/bin/matlab

csusap.csu.edu.au% netstat -atn|grep 6010
netstat: illegal option -- t
usage: netstat [-anv] [-f address_family]
       netstat [-g | -p | -s] [-n] [-f address_family] [-P protocol]
       netstat -m
       netstat -i [-I interface] [-an] [-f address_family] [interval]
       netstat -r [-anv] [-f address_family]
       netstat -M [-ns] [-f address_family]
       netstat -D [-I interface] [-f address_family]

csusap.csu.edu.au% echo $DISPLAY
DISPLAY: Undefined variable

csusap.csu.edu.au% xterm &
[1] 29958
csusap.csu.edu.au% xterm Xt error: Can't open display:

[1]    Exit 1               xterm

If this is indeed the case, then at least I have something definate to ask the 
lecturer to do something about.  Getting him to act on it is another matter 
altogether.

sue