Would anyone have any idea why I cannot connect to Kubuntu outside my network, from work for example.

I have all relevant ports forwarded. I can connect from other computers inside my network, but when I try from the outside using Tight or Real VNC I can't connect. This used to work fine using Gnomes remote desktop.

I gave allowed uninvited connections, removed the need for confirmation and allowed control of dekstop but I still can't connect and am totally stumped as to why...

Any ideas?