I took this from another website, but it worked out for me, and I needed it in order to attach to VNC on a non standard http port.
It seems as a security touch to Firefox it is now blocking non standard HTTP ports. Kinda of annoying really. To override this type this in the address bar "about:config" and search for "network.security.ports.banned.override". This may or may not exist, if it doesn't, right click anywhere in the window and select new->string and use "network.security.ports.banned.override" as the name and the port number you need to connect to as the value. You can also select a range of ports by using "1-1024" as such a value or as a CSV style values such as "1024, 8080, 1-1000, 80"… etc

[this is good] Rather quite good topic
Posted by: Elvin Frizzell | 06/08/2010 at 02:33 PM