Maybe I was not very clear.
So I am at home with ADSL connection. I have full control of my environment.
My son, is studying and his PC is behind a "corporate" firewall. His address is a 10,x,x,x range and seems static.
He can initiate a PuTTY session from his position and connect via DynDNS to my PC.
However the objective is that I need to connect to his PC and conduct some changes.
In Win I would use LogMeIn as a service and in fact I do so with his laptop; however this is Ubuntu on both ends thus PuTTY or VNC from either end cannot connect.
How do I over come this?