Connection refused with firefox

Since installing Fedora Core 3 on my laptop I have been unable to access web sites with Firefox on an intermittent basis. The usual pattern is that google and most search engines produce a 'Connection refused...' error. What's doubly annoying is of course the first thing you do on getting an error like this is to google the answer! How many times did I try to do that - doh!

There were certain other sites I couldn't access too. I downloaded Knoppix and ran linux from a CD but still had the same error.

I read around and tried a few things. Eventually I came across a site (can't remember which one) that advised changing the behaviour of the browser that does a lookup on IPv6 names. Type 'about:config' in the address bar, scroll down to 'network.dns.disableIPv6' and set it to 'true' from the default 'false' (it's a double negative). For me that solved it. I hope by posting this it makes the information more available on google :o