X11 Forwarding
X11 forwarding is needed to start an X Window (X11) graphical user interface on a remote computer.
Note that X11 forwarding has security implications and therefore
should only be enabled when necessary (see man ssh). The
ssh command line option for enabling X11 forwarding is
-X.
The login gateways of Hummel-2 have no X11 software installed. To
enable X11 forwarding the login gateway must be used as a jump
host to a front-end node by using the -J option:
$ssh -X -J bxy1234@hummel3.rrz.uni-hamburg.de bxy1234@front1
As a prerequisite your public key must be added to the
authorized_keys file on Hummel-2. This can be done with the
ssh-copy-id command (note that the private key
file is specified with the -i option while the
public key is being copied):
$ssh-copy-id -i ~/.ssh/id_hummel bxy1234@hummel3.rrz.uni-hamburg.de
Under Windows ssh-copy-id is available in MobaXterm. Keys generated with
PuTTYgen
must be converted with PuTTYgen to OpenSSH format before (load existing
.ppk key file and click Export OpenSSH key in the
Conversions tab).
To test X11 functionality there is:
- the
xlogocommand which shows the X11 logo on your desktop, - the
xeyescommand – the follow the mouse demo. - Commands on a Hummel-2 front-end node:
bxy1234@hummel2-front1:~$module load xlogo bxy1234@hummel2-front1:~$xlogo bxy1234@hummel2-front1:~$module load xeyes bxy1234@hummel2-front1:~$xeyes