# iptables -L
FATAL: Module ip_tables not found.
iptables v1.4.14: can't initialize iptables table `filter': Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.
# uname -a
Linux rpi 3.1.9+ #1 PREEMPT Wed Jun 6 16:26:14 CEST 2012 armv6l GNU/Linux
# zgrep ip_tables /proc/config.gz