sudo iptables -t nat -A POSTROUTING -o tun0 -j MASQUERADE
sudo iptables -t nat -A PREROUTING -p tcp -d 1.2.3.4 --dport 8080 -j DNAT --to-destination 192.168.0.2:80
sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
sudo echo net.ipv4.ip_forward=1 >> /etc/sysctl.conf
sudo sysctl -p