Commands to set up port redirection on ubuntu

Port Redirecting

//list current rules
sudo iptables -t nat -L --line-numbers

//delete rule for port <n>
sudo iptables -t nat -D PREROUTING <n>

//redirect port 80 to port <n>
sudo iptables -A PREROUTING -t nat -i eth0 -p tcp --dport 80 -j REDIRECT --to-port <n>

//Save settings (need package iptables-persistent installed)
sudo iptables-save >/etc/iptables/rules.v4