Internet connection failure using IPv6

Q I have tried several distros including Fedora, Mandriva and SUSE, and I always have the same two problems. The first problem is that Firefox rarely manages to connect to the internet, giving a 'timed out' message, which I also get if I try to update the system, while Konqueror has no problems. The second problem is that after anything from a few minutes to an hour or two, the screen will freeze and not respond to the mouse pointer, which is still able to move. I am using an Nvidia graphics card but had tried unsuccessfully several times to install the proprietary driver for it. I tried Ubuntu Feisty after reading that it had a simple method of installing the Nvidia driver. This worked very easily and now my screen no longer freezes.

I have also found that Firefox works on Feisty too, and so do updates. Then I decided to try Ubuntu Gutsy on another partition. I found that the Nvidia driver would not install on Gutsy as the internet connection could not be made, even after trying a different download server, and updates would not work either. My problem with Firefox also returned, although Konqueror still worked with no problems. Is this a problem with my hardware or settings, and why does Ubuntu Feisty work?

A Your internet connection problem is almost certainly caused by your browser trying to talk to your modem or router using IPv6. If the connection does not work with IPv6, the system is supposed to fall back to using the older IPv4. However, some routers do not do this and get confused when dealing with a client that talks IPv6 and an upstream connection (your ISP) that does not. There are three ways to deal with this: fix the router, disable IPv6 at system level or disable it in the browser. It would be worth checking the router manufacturer's website to see if there is a firmware upgrade available.

The problem may completely disappear after doing this. If not, you can tell your computer not to use IPv6 so Firefox, or any other program, doesn't even try to communicate with the router in this way. You disable IPv6 by adding or editing these two lines in your modules configuration file. This is /etc/modprobe.d/aliases in Ubuntu, but can be /etc/modprobe.conf or /etc/modules.d/aliases in other distros.

alias net-pf-10 off
alias ipv6 off

These should replace any existing lines that refer to IPv6. The third option, which should only be used when neither of the others is possible, is to disable IPv6 in Firefox, which won't help with anything else. Type about:config into Firefox's location bar, then IPv6 in the Filter box. If network.dns.disableIPv6 is set to false, right-click on it and pick toggle from the menu to change it to True. Most distros now have the Nvidia drivers in their repositories, but installing them is fairly simple if you download the package from www.nvidia.com. Press Ctrl+Alt+F1 to switch from the desktop to a console, log in as root (or run sudo -i from Ubuntu) then execute these commands

init 3
sh NVIDIA-Linux-XXXX-pkg1.run
nvidia-config
init 5

Debian and Ubuntu users should replace the first and last commands, which turn off and on the X server, with

/etc/init.d/dm stop
/etc/init.d/dm start

The Nvidia installer bails out if X is running, hence the need to switch to a console and disable X. Part of the installation process may involve compiling a module for your kernel, if this fails, make sure the build-essentials package is installed. Nvidia-config modifies your X configuration file to use the new driver.

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