How to Disable IPV6 in Ubuntu

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If you disable IPv6 and get reasonable Internet connection & DNS speeds

Method 1

You need to edit the aliases file using the following command

gksudo gedit  /etc/modprobe.d/aliases

Find the line: alias net-pf-10 ipv6

change to

alias net-pf-10 off

If the above change is not working you need to change the following one

alias net-pf-10 off ipv6

Save the file and reboot


Disable IPv6 in Firefox. Type about:config and search for:


and set it to TRUE

Method 3

Edit /etc/default/grub file

gksudo gedit  /etc/default/grub




GRUB_CMDLINE_LINUX_DEFAULT=”ipv6.disable=1 quiet splash”

Save and exit the file

Update the grub from the command line

sudo update-grub

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27 Responses

  1. bart says:

    Could you please explain me why would I disable IPV6 ? for which reason ?

  2. admin says:

    some people might get slow network/Internet connections, DNS resolution problems.If you disable ipv6 these two problems will be fixed.

  3. You should not disable IPv6 because it is the future and the Web is moving towards it… Most hosting providers have updated and there is a good chance just 10% og your requests needs to be resent in IPv4.

    If you need faster DNS you should rather look at a different DNS provider. Consider switching to OpenDNS for example! They are really fast and you get URL typo-correction and lots of other useful features.

  4. Alex says:

    There are some few software (for example, VMWare Server 2) doesn’t work with Ubuntu and IPV6. This could be one reason.

  5. t0m5k1 says:

    i think that if IPv6 is not utilised within a LAN nor has the LAN external access to IPv6 networks then it is not needed & could cause unexpected issue’s therefore it should be disabled.
    Yes the future of the inet is with IPv6 but at the moment not enough ISP’s use it or offer it so it is only usefull in development environments.

  6. Jon Determan says:

    I disable IPV6 bacuse the campus I am on doesnt support IPV6 and internet doesnt work at all if IPV6 is enabled

  7. raindog469 says:

    I’m behind an ipv4-only router. ipv6 may be the future, but the future is not here yet.

  8. Would’nt it be the right way to disable/blacklist the ipv6 kernel modules in /etc/modprobe.d/blacklist?

  9. Nick says:

    … for security reason. There are a lot of machines using tunneling of ipv6 over ipv4 (e.g.teredo in windows) to overcome firewall rules of the admins and expose that way the corporate networks to the outside world. What sense make firewalls and NAT adresses, when they just get traversed by ipv6 traffic.

  10. boold says:

    also for security reasons, several services had remote exploits in their ipv6-implementation, more will come.

  11. hardy stevenson says:

    in jaunty the aliases file is empty. But the probs
    seem to most effect the http://www…so doing about:config
    in firefox/ network.dns.disableIPv6 changed to true
    made me happy enough…
    the reasoning behind diabling IPv6 is that its
    too early and IPv4 still dominates by far way far.
    so it avoids hangups to revert…tootles

  12. Farry_2012 says:

    Thanks for the information. Remarkable blog;)

  13. Jonn says:

    Cool blog! Thanks for the information. Add to favorites;)

  14. Klio? says:

    Useful information! Thanks to author!

  15. Michael says:

    I had to edit the file “menu.lst” there was no “grub” file to edit that I could find – but that did the trick. Thanks for the info. My e-mail is now much faster.

  16. lars says:

    The information will be useful to many. Thanks to author!

  17. Jim says:

    Even if your isp is using ipv6 your modem/gateway most likely is using nat/pat to translate it to a ipv4 private address. Unless you have a machine right up against the interenet, like a webserver, you probably dont need ipv6.

  18. Juan says:

    I’m running 9.10 32-bit server, but do not see the aliases file.

  19. toniisam says:

    I am running 9.10 at home and cannot get any internet access, not with a web browser or to do updates. In 8.10 and 9.04 this worked straight after installing. The file /etc/modprobe.d/aliases does not appear to be there.
    Perhaps the file is somewhere else, or the system is different in 9.10. Fortunately I also have 9.04 installed and that works, but I have heard about lots of problems with 9.10. Hope they get them dealt with for the next long-term support release.

  20. Andrew P. says:

    Re: Comment by toniisam on January 27, 2010

    I believe you’re correct. I tried upgrading from Ubuntu 8.10 to 9.04, and it worked HORRIBLY. It caused the Firefox and SeaMonkey browsers talking through my Netgear WGR614 wireless router to slow to a crawl — about 1/10th the speed that my Windows computers run. At the time I couldn’t find an answer to my dilemma, so I had no choice except remove 9.04 and revert to 8.10, which I’m still using. I later read that Ubuntu 9.04 had IPv6 enabled by default. I also understand that most consumer network equipment doesn’t support IPv6 natively today, including the WGR614, although there is a way of doing it indirectly by “tunneling”. It’s a shame that Canonical Ltd. released this abomination on the user community. IPv4 should be enabled by default, with IPv6 available for those whose network environments support it. IPv6 may be the future of the Internet, but, as others have commented above, the future isn’t here yet.

  21. Andreas N says:

    Using sysctl you can disable IPv6 on the running system without rebooting:

    sysctl -w net.ipv6.conf.all.disable_ipv6=1

    To disable permanently add “net.ipv6.conf.all.disable_ipv6=1” to /etc/sysctl.conf.

  22. Jonathan says:

    I also have terribly slow internet on my usually trusty Ubuntu machine when upgraded to 10.04. It was fine during my first try out with the Live cd and immediately after install but once rebooted all networking slowed to a crawl. I’ve tried disabling ipv6 in Firefox without success. I also tried reinstalling on that machine with the same results.

    The same version of Ubuntu works fine on my Netbook though.

    i can’t find the aliases file to modify.

  23. IPv6 is disabled through your info but what is the issue with this.

  24. Andy says:

    to /etc/sysctl.conf and run sysctl -p.

    Everything else is more less “wrong”. May want to reflect that in your blog.

  25. stanz says:

    Using 10.04 with updates-
    same as above- no “aliases” file found!

    some change is just a pain to users!!!

  26. aprte says:

    Thanks! very useful information.

  27. MarvinPa says:

    @Daniel Aleksandersen, this is the future posting. IPV6 is still not in wide use and is still causing all kinds of problems.

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