Specifically downloads x64 packages only from apt repository.

Comment out /etc/dpkg/dpkg.cfg.d/multiarch.
Introducing the iptables rules.

Put the iptable-save script onto /etc/network/if-down.d/iptable.
Add script for restoring the iptables setting onto /etc/network/if-up.d/iptables.

And finally, put the seed iptable rule file onto /etc/iptables-rules.
Merge branch 'base'