[Bdi4emc-help] Re: consequences of new OpenSSH...

Tue Dec 13 14:22:42 CET 2005

Paul: wrote

>Distilled the info down to it's minimum and confirmed it works on a fresh 
>BDI-4 install. I did notice that the setting of DISPLAY was not needed as the 
>-X flag should automatically set the variable.
>  
>
Just to make sure we're on the same wavelength, I spoke of two different 
approaches:

(1) forwarding X11 communication through ssh, in which case one does 
*not* need to set up *either* the local xhost list (which will be 
ignored because the X11 channel isn't being used) or the remote DISPLAY 
variable (which is set automagically by the remote sshd during the logon 
handshake to a pseudodisplay number; on my BDI-4.30 machine it's 
DISPLAY=localhost:10.0; your mileage may vary).

(2) normal X11 communication via the X11 channel, in which case one 
needs to set up *both* the local xhost list (otherwise the remote X11 
client will be ignored) and the remote DISPLAY variable (so the X11 
client knows who to talk to).

If you're invoking ssh -X or ssh -Y you're using the first approach, 
which is preferred for security reasons. I spoke of the second approach 
to help those who couldn't get X11Forwarding to work for their EMC 
installation because of the untrusted X11 client problem.

Regards,
Kent