My problem is solved, at least for now. My reservation is becauser I don't know what I did.
Last night I tried to be sure I had no filters interfering., I turned off the firewall, booted and tried firefox and dillo. Neither worked. I made selinux permissive, rebooted and tried dillo and firefox. Neither worked. I went to bed. This morning I tried Puppy Linux, and it worked fine. So I tried ubuntu, and that worked fine. ( I had failed with both of them yesterday.) So I booted fedora and firefox -- success.
I was baffled in the beginning, and I am more baffled now.
I thank you all for your efforts. I tried ( to the best of my abilities) to implement all the suggestions, but I don't believe I ever really changed anything permanently.
I am OK for now, but Who knows; maybe it only works on thursdays.