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

[John Clarke]

On Mon, Mar 15, 2004 at 08:43:45 +1100, Sue Stones wrote:
> On Mon, 15 Mar 2004 06:08 pm, John Clarke wrote:

> > 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.

That's your problem.  X11 forwarding isn't enabled.  ssh always sets
$DISPLAY if forwarding is enabled.

> (I have an ordinary user account on the remote host.)

The example I posted was using an ordinary user account, so it's
nothing to do with that.  It is possible to disable x11 fowarding per
user, but that's done via the authorized_keys file (and is only
relevant when using rsa authentication) which the user can change.

> csusap.csu.edu.au% netstat -atn|grep 6010
> netstat: illegal option -- t
> usage: netstat [-anv] [-f address_family]

I don't know which Unix you're using, but I'd guess from the ouput that
you want 'netstat -an -f tcp', or even just 'netstat -an'.  It doesn't
matter though - if $DISPLAY isn't set, there'll be nothing listening.

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

No $DISPLAY == no X11 forwarding.

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

That's understandable, it doesn't have a display to work with.

> If this is indeed the case, then at least I have something definate
> to ask the lecturer to do something about.  

Yes, and it's a very easy thing to fix - five seconds to change
sshd_config and restart sshd.  They may have a good reason to disable
x11 forwarding though - it can use a lot of bandwidth.

> Getting him to act on it is another matter  altogether.

That's something I can't help you with :-)


Cheers,

John
-- 
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