I use Cygwin/X to ssh into a VirtualBox hosted Ubuntu Server which has had the various X bits and pieces installed:
ssh -X user@IPADDRESS
Once in, I can run
gnome-terminal and the terminal pops up. Once in there I can open new tabs, run
geany (a text editor like GEdit) and so-on, and it all works, the windows open and everything is fine.
Then, at some point, something happens and I am unable to open any new applications that make use of X. Existing applications function fine, but anything new will complain that it can't open the display. eg:
user@SERVER:/mnt/smb$ geany Geany: cannot open display
I think this starts happening after I have used sudo to execute a command such as:
sudo apt-get install XXXX
After the problem starts, the
DISPLAY environment variable is the same as it was before.
The only other piece of information that may be of use is that when I first log in to the machine, the following appears immediately after authentication:
Warning: untrusted X11 forwarding setup failed: xauth key data not generated Warning: No xauth data; using fake authentication data for X11 forwarding.