IPv6 is slowly becoming more prevalent, and Ubuntu comes ready to make use of it.
This can cause your Internet network access to be a bit slow, however, if you don’t have IPv6 service as new connections will have to wait for the IPv6 to timeout.
In Saucy Salamander (and earlier, up to 12.04 if I recall), you can turn off IPv6 to speed things up. (Please, if you use IPv6 for anything, don’t do this.)
Use you favorite editor to add a few lines to /etc/sysctl.conf: (Here I use gedit)
gksudo gedit /etc/sysctl.conf
I added these to the bottom, just to make it easy to find. This turns off all IPv6 in your networking.
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
Save and close. To make this work:
sudo sysctl -p
This will take effect right away.
Hope this helps!