Hi all,

I'm having a problem setting up an SSH connection with X Forwarding in a very 
special setup, and hope you will be able to help me.

The setup is as follows: I live in a student residence and have a computer 
there named ririu. This computer isn't reachable from the outside, as the 
university's computer center blocks all ingoing connections to the residence 
from the outside.
The only reachable computer from the outside is our server in the residence, 
hal, for which the computer center makes an exception.

I'm now at my parent's place and want to build up an SSH connection with X 
Forwarding from my computer here, freya, to ririu, my computer in the 
residence. As hal is in the same LAN as ririu, obviously I can connect from 
freya to hal, and then from hal to ririu.

So I can also log in to hal and do a

[EMAIL PROTECTED] $ ssh -g -L 2508:ririu:22 [EMAIL PROTECTED]

to build up an SSH tunnel. Then I can connect from freya to ririu using

[EMAIL PROTECTED] $ ssh -p 2508 [EMAIL PROTECTED]

This works like a charm. However, now I also want to have X Forwarding ;)

So I tried to specify -X as an additional parameter.

[EMAIL PROTECTED] $ ssh -p 2508 -X [EMAIL PROTECTED]

I do succeed in connecting to ririu. Except that the X forwarding doesn't work!

[EMAIL PROTECTED] $ firefox
Error: no display specified
[EMAIL PROTECTED] $ echo $DISPLAY

[EMAIL PROTECTED] $

An X Forwarding to hal works flawlessly:

[EMAIL PROTECTED]:~$ ssh -X [EMAIL PROTECTED]
[EMAIL PROTECTED] $ echo $DISPLAY
localhost:11.0

...I can start X applications on hal and they are displayed on freya. But as 
you see, when I try to this from freya through an SSH tunnel from hal to ririu, 
the DISPLAY variable somehow gets lost. It doesn't help to randomly set the 
DISPLAY variable on ririu to localhost:11.0 or localhost:10.0 either, which I 
tried in desperation.

I hope I made it clear what the problem is, otherwise just ask :)
Do you have any idea why this isn't working? I would have assumed that ssh 
doesn't even notice it's running through an SSH tunnel and that this should 
hence work without problems. But it doesn't... so, is there any way for me to 
build up an ssh connection with X forwarding from freya to ririu at all?

Thanks for your help :)

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