Karmic: IPv6 Woes – Long as I Can See the Light

I did a great deal of searching in regards to the slowness issues and the IPv6 DNS issues in Ubuntu 9.10. As with any issues in Ubuntu I am always happy as Long as I Can See the Light and Lucky for me JoeHacker left a candle in the window.

Using yout favorite editor using sudo, edit /etc/default/grub and change:
GRUB_CMDLINE_LINUX_DEFAULT=”ipv6.disable=1 quiet splash”
sudo update-grub

This worked wonders for me in my test VM and I will soon test this on my main machine. Despite the fact that I was not born with a silver spoon in hand Joe’s advice has made me feel like a Fortunate Son. One important note is that this may not be an issue with Ubuntu, but an issue with how IPv6 DNS requests are being handled by my router.

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18 Responses to Karmic: IPv6 Woes – Long as I Can See the Light

  1. Craig says:

    IPv6 is a growing part of the Internet, and in the coming years, will be very important. Simply disabling IPv6 claiming to fix a problem, then advising others how to do so, is highly irresponsible.

    Please researching and fix the actual problem, instead of publicizing this crippling work around.

    • Charles Profitt says:


      Crippling work around? As of right now this is the only ‘fix’ I have seen. As I am not a programmer for the Kernel nor Ubuntu I will leave it to them to find a ‘permanent fix’ if there is one. There was a launchpad bug report posted back in August on this issue and it was claimed that the issue is in the fact that my router does not handle IPv6 DNS requests properly. I am sure that some things can be done to fix the issue, but that is likely up to the MOTU. For now the solution I posted works. If you know of a ‘better’ fix Craig then please feel free to post one. While IPv6 will be important in the future right now there are issues with support for it from ISPs to home networking equipment.

    • Dan says:


      I work for a large company that has locations world wide. I am very tired of people talking about IPv6 like it’s the Holy Grail. Yes it’s an up and coming standard but with a WAN the size that my company has there are many locations that have routers and switches that are not IPv6 capable.

      I have had entire locations that had crippled WAN connectivity because I put a Ubuntu server in place that didn’t have IPv6 turned off. Yes we should put in new switches and routers but the way the business climate is I’m lucky to get replacement parts when things break. My management could care less if I can’t run Ubuntu so either I turn off IPv6 or I stick with Windows – which of course lets you turn off IPv6.

      So get off your high horse and join the real world!


  2. A bit crazy turning of IPv6. More and more places I am connecting my laptop too these days give me an IPv6 address. I have one at home also.

    If your router DNS server is broken then a better solution might be to suggest people use a public DNS server rather than using the broken on on the router.

    You post sort of implies that IPv6 is broken in Ubuntu. Nothing of the sort.

    • Charles Profitt says:

      If taken on its own one might take it that way, but my previous post indicates that the issue is related to my router.

  3. doug says:

    This was this same problem in 9.04 also. At some point, in one of the kernel image updates they put out, it was corrected for me.

    For 9.10, there should be a boot parameter you can add to your menu.lst that corrects this problem. I’m too lazy to look it up now, but I believe I found it on Ubuntu’s forums. Anyway, I suppose it is about the same thing as your solution.

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  5. Pingback: Charles Profitt: Karmic: IPv6 Woes – Long as I Can See the Light | TuxWire : The Linux Blog

  6. meric says:

    why not adding other DNS like opendns to your resolv.conf ?

    that is what i’ve done because my fai have bad dns

  7. DrScott says:

    Some routers are still using a dns cache called “dproxy”. This small software is hosted on sourceforge. There’s also an bug which describes something that could be your problem:


    Very simple solution: Switch off the routers dns cache and set up one locally on your system or just use your ISPs dns server directly.

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  9. Jeremy says:

    You know, if you just configured your network to run IPv6, you wouldn’t have any performance issues. It’s even less work than your work around…

    • Charles Profitt says:

      I have checked with the manufacturer of my home router and it does not appear to have support for IPv6 at this time. At work there is not an issue, but home is another story.

      • Then if it’s Ubuntu 9.10, do this:

        sudo apt-get install miredo
        sudo vim /etc/default/miredo **change the default start to YES**
        sudo /etc/init.d/miredo start

        voila.. you have IPv6.. Like I said so much easier..

  10. Ad says:

    Don’t listen to the negative comments.

    Not all of us refresh our home routers every 6 months, and so most of us are stuck with routers that don’t handle IPv6. Enabling IPv6 in Karmic by default was probably the right choice (it *will* be important very soon), but in the mean time, it downright ruins internet performance in Karmic. Nobody is to blame, things need to move forward, but for now your fix makes my laptop work.

    In 6 months time I may have a new router, I may not be able to access some websites without having IPv6, I may even have a v6 IP myself, but, until then….

    Thanks for posting the info🙂

  11. mathew says:

    If you really don’t want to fix your router, another option is to install and use dnsmasq. That’ll likely make your web browser much faster too.

  12. resDeerry says:

    I really enjoyed reading this article, keep up posting such interesting articles.

  13. Pingback: Slow Internet On Karmic | My PC’s

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