The Ubuntu development team have enabled the newer Internet protocol, IPv6, by default. However, a lot of older hardware — such as NICs and modems — only supports IPv4. This leaves you wondering why Internet applications take so long to work.

The following instructions disable IPv6 support, allowing users with incompatible hardware to get normal connection speeds and DNS resolving.

Disabling IPv6

for ubuntu

1.  sudo gedit /etc/modprobe.d/bad_list 

2. Add this line:  alias net-pf-10 off 

3. Save the file and restart your computer

for kubuntu

1.  kdesu kate /etc/modprobe.d/bad_list 

2. Add this line:  alias net-pf-10 off 

3. Save the file and restart your computer

You must reboot for changes to take effect.

Once you have configured all this try this is a terminal:

 ip a | grep inet6 

If there's no output it means ipv6 is effectively disabled.

Mozilla web browsers

With Mozilla web browsers, enter about:config in the address bar and then type ipv6 in the Filter field. Double-click the only listed item, network.dns.disableIPv6, and then close the browser.

CategoryDocumentation CategoryCleanup