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 myserver.fqdn:10.0 # 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