I installed VNC server on my system and enabled the ports in /etc/xinet.d/vnc. Then I was able to connect from Windows with UltraVNC and RealVNC. But every time when I entered my userid and password the connection was dropped. I found following message in the syslog:
Nov 27 19:34:19 obelix checkproc: checkproc: can not get session id for process 5920
I found following page which helped me to find the solution for the issue: In /etc/hosts I had to comment out the following line (insert # at the beginning of the line ) and everthing works fine now.
#::1 localhost ipv6-localhost ipv6-loopback