I am new to Ubuntu (11.10) - I installed Ubuntu on a box which has no screen and no keyboard. I connect to that box via tightvncserver. The box is mostly used as a file and media server (i.e. samba + XBMC). So far so good. I can connect via VNC to the box and take control of it. But after a few days, when trying to connect via VNC, I don't get a response. The media server is still on, ping is fine, but VNC is down. The only solution I have found is to plug a screen and keyboard and reboot. I am not sure how to diagnose the problem (maybe some log files?) or if this is just a configuration issue. Any help appreciated.