[arch] Please write me an iptables rules file

[Richard Maxwell Underwood]

I'm not a Linux newbie, but I haven't learned iptables or
netfilter, and it would be _so nice_ if I didn't have to study
detailed documentation to make the following change to my
machine.

I know that many people don't want this mailing list flooded by
"newbie" questions about Linux, but please let me have one
reprive from this general rule or ethic against "newbie"
questions.

The only network connections on my machine are lo and ppp0.

I want to prohbit all systems except for localhost from
initiating a connection to my machine.

I know that this breaks active ftp, but I think that's ok
because pacman uses passive-mode ftp.

Could someone post an /etc/iptables/iptables.rules?