Fix to make Firefox FLY (really fast)
It's really easy but it's not decently explained in the manual -- but you can make Mozilla realy Fly (resolves loads of problems with DNS resolving and slow URL resolution on a lot of sites)
1) in the navigation toolbar (where you enter the site you want to get to) click the following (it's not a typo) about:config
now scroll down to Network.dns.disable IPV6
right mouse click and select toggle (this actually disable the IPV6 which is fine for most of the "normal" type Internet users going via ISP's.
There might be more stuff in these options --haven't explored them all yet but this definitely solved all my DNS probs -- now my Network is really set up using DHCP without having to enter any DNS names etc etc.