I have a 3rd party java app that I need to run on a remote server. Unfortunately, the app is designed for the desktop and assumes a GUI is available. The thing is I would like to leave this app running on the remote server without having to tie up my desktop machine with a persistent VNC connection to the remote machine. I'm trying to setup Xvfb on the remote machine so emulate a graphical environment, connect to the remote machine via VNC to launch the app and configure parameters and then log off and let it run. Here's what I have so far: I have ubuntu 11.04 server apt-get install xvfb apt-get install fluxbox apt-get install x11vnc Xvfb :1 -screen 0 1024x768x16 & fluxbox & At this point I run into a problem because it gives a very undescriptive error: Cannot connect to server. How do I know if the server is running and that it's running properly?