I run https://jamesmcdonald.id.au with a self signed untrusted certificate because I'm not using it for commerce and the only person who needs to trust it is me!

But after installing Fedora 9 on a laptop and trying to connect to my website. I didn't get the normal add exception page but an annoying alert with text in it some of which was:
"Error code: sec_error_untrusted_issuer"
The only option was to click OK but no add exception page appeared.

Attempts to fix
I tried going into Preferences ==> Advanced ==> Encryption ==> Certificates ==> Servers ==> Add Exception and typing in https://jamesmcdonald.id.au and it still wouldn't allow me to add an exception.

Because I was accessing the site from my home LAN I also tried simply entering the local IP address https://192.168.88.22 but that didn't work either.

It seems that Firefox _really_ doesn't trust something on the local network with a self signed cert.

The solution
From the Fedora 9 box su to root and then ssh to the server box mapping the local port 443 to the web servers port:

ssh -L 443:localhost:443 192.168.88.22 -l username

Then in Firefox just connect to https://localhost and for some weird miraculous reason you will then get the Add Exception webpage. Add your exception and you're done

This is a weird error... hopefully this work-a-round will help.