[CentOS] ssh x11 forwarding problem

Fri Feb 17 15:02:18 UTC 2006
Tony Schreiner <schreian at bc.edu>

I'm running into an a problem with x11 forwarding over ssh

I'm trying to run an application (rasmol -  molecule viewing program)  
which when using the the default setup for x11 forwarding causes the  
following error:

X Error of failed request:  BadAccess (attempt to access private  
resource denied)
   Major opcode of failed request:  132 (MIT-SHM)
   Minor opcode of failed request:  1 (X_ShmAttach)
   Serial number of failed request:  230
   Current serial number in output stream:  231

It used to be possible to overcome this by setting

X11UseLocalhost  no

in /etc/ssh/sshd_config

This worked in CentOS 3 but does not in CentOS 4 (or Fedora 4 for  
that matter), and I'm guessing it is a XFree86 vs. Xorg issue.

Now, when using
X11UseLocalhost no

no X applications work

ssh myserver
# echo $DISPLAY
# xdpyinfo
xdpyinfo:  unable to open display "myserver.fqdn:10.0".

I have X11 forwarding set up on the client side by default.

on the other hand if I don't use tunneling, but set  DISPLAY=myclient: 
0 and xhost +myserver on the client
then the application works.

I prefer to use tunneling if possible.

Thoughts about why X11UseLocalhost doesn't work?
Tony Schreiner