iptables port forwarding

clear-iptables.sh

sudo iptables -F
sudo iptables -X
sudo iptables -t nat -F
sudo iptables -t nat -X
sudo iptables -t mangle -F
sudo iptables -t mangle -X
sudo iptables -t raw -F
sudo iptables -t raw -X
sudo iptables -t security -F
sudo iptables -t security -X
sudo iptables -P INPUT ACCEPT
sudo iptables -P FORWARD ACCEPT
sudo iptables -P OUTPUT ACCEPT

sudo ip6tables -F
sudo ip6tables -X
sudo ip6tables -t nat -F
sudo ip6tables -t nat -X
sudo ip6tables -t mangle -F
sudo ip6tables -t mangle -X
sudo ip6tables -t raw -F
sudo ip6tables -t raw -X
sudo ip6tables -t security -F
sudo ip6tables -t security -X
sudo ip6tables -P INPUT ACCEPT
sudo ip6tables -P FORWARD ACCEPT
sudo ip6tables -P OUTPUT ACCEPT

iptables.sh

# Local testing
sudo iptables -t nat -A OUTPUT -o lo -p tcp --dport 80 -j REDIRECT --to-port 4000
sudo iptables -t nat -A OUTPUT -o lo -p tcp --dport 443 -j REDIRECT --to-port 4001
sudo ip6tables -t nat -A OUTPUT -o lo -p tcp --dport 80 -j REDIRECT --to-port 4000
sudo ip6tables -t nat -A OUTPUT -o lo -p tcp --dport 443 -j REDIRECT --to-port 4001

# Production
sudo iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 4000
sudo iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 443 -j REDIRECT --to-port 4001
sudo ip6tables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 4000
sudo ip6tables -t nat -A PREROUTING -i eth0 -p tcp --dport 443 -j REDIRECT --to-port 4001