Some may find that out-of-the-box, Hardy Heron’s network performance is painfully slow. By default, IPv6 is enabled, and chances are good that your nearest router can’t speak the language nor interpret DNS requests efficiently.
To disable IPv6, open a shell and append the following to /etc/modprobe.d/blacklist:
# disable ipv6
To verify that IPv6 is disabled, run
lsmod | grep ipv6
ip a | grep inet6
The commands shouldn’t return any information. Firefox browsing speeds should be much improved.