Disable IPV6 in Ubuntu Dapper and Feisty

Turning off ipv6 is helpful in some circumstances. For example if your network is slow. If your router is only IPv4 enabled,  the IPv6 Protokoll is tunneled via IPv4.

First check if IPv6 is running on your system. Use the following command: 

ip a | grep inet6 

To disable IPv& you may want to edit the aliases file. Use your favorite Editor, for example joe.

sudo joe /etc/modprobe.d/aliases

and change the line:

alias net-pf-10 ipv6 

to:

alias net-pf-10 off ipv6

Reboot your box and IPv6 is history on your system.