NAT forwarding under Linux
Easy setup of NAT forwarding using iptables under Linux (this was only tested on Fedora 18):
EXTERNAL=wlan0 INTERNAL=p3p1 sysctl -w net.ipv4.ip_forward=1 iptables -F iptables -A FORWARD -i $INTERNAL -j ACCEPT iptables -A FORWARD -o $INTERNAL -j ACCEPT iptables -t nat -A POSTROUTING -o $EXTERNAL -j MASQUERADE