Well I've managed to persuade my Fedora system that it has a fixed network address but it *still* won't talk to the outside world. The symptoms are exactly the same as they were before:-
I can 'host xxx.yyy.zzz' and I get the right IP address back for whatever I've asked for.
I can't ssh, ftp or anything to anywhere outside my local subnet.
All other systems on the subnet *can* talk various protocols to the outside world. The Fedora system can talk various protocols to other systems on the same subnet.
So can anyone offer any insight, I'm at the swearing at it stage!