Disable IPv6 If your Internet is Working Slow in Ubuntu 12.04

To do this open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal:

• sudo gedit /etc/sysctl.conf

Now add these lines at the end of file:

# IPv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1 

Enter following command to restart sysctrl settings:

• sudo sysctl -p

DNS in Ubuntu 12.04

Switch to resolvconf for /etc/resolv.conf management