Re: SSH Tunneling of X protocol from non-interactive session

From: Mihai Osian (zzz_at_zzz.com)
Date: 10/10/05


Date: Mon, 10 Oct 2005 11:40:21 +0200

Dobes Jiri wrote:

> Hallo,
>
> I need to forward X terminal through the firewall from non-interactive
> session.
>
>
> Situation:
> M - my computer
> F - firewall
> C - cluster with application
>
> M --- F ---- C
>
> The final point is to run a X application on C from a queuing system
> and display on M.
>
> First setup simple test. I am sitting at M. I would like to open
> tunnel from C to M tunneling X protocol.
>
> M> xhost +
> M> ssh -x C
> C> ssh -L6001:localhost:6000 M
>
> Now I try to run application on C and forward the X protocol to M.
> Open another termimal (still leaving the tunnel opened) and
>
> M> ssh -x C
> C> export DISPLAY=C:1
> C> xterm
>
> and error message appear:
> xterm Xt error: Can't open display: C:1
>
> Does anybody know why? Is there a problem with authorization? On M all
> the connections are allowed (it was xhost +).
>
> If this would work I would write a script creating tunnel from C to M
> and running the application on C with display C:1 forwarded to M. When
> the script is executed terminal would open on my desktop...
>
>
> Thanks for all the help!!!
>
>
>
> Jiri
>
>
> P.S.: I use OpenSSH_3.7.1p2, however I don't think it is important...
>

First remark: why exactly do you want to forward the X connection
manually instead of letting ssh do the dirty work (M>ssh -Y C) ? You
lose the encryption.
Second: Are you sure that X is listening on localhost:6000 on M ? It
might be possible that the X server was launched with the -nolisten flag.

Mihai