So, to keep it short and simple: assume you’d like to forward any traffic coming to your machine (192.168.0.1) on port 80 to machine2 (192.168.0.2) on port 8080 then:

- Enable port forwarding:

echo 1 > /proc/sys/net/ipv4/ip_forward

- Now add the rules:

iptables -t nat -A PREROUTING -p tcp -d 192.168.0.1 –dport 80 -j DNAT –to 192.168.0.2:8080

iptables -t nat -A POSTROUTING -d 192.168.0.2 -j MASQUERADE

The -p tcp flag specifies that the protocol is TCP (as opposed to UDP, ICMP for example).

The -d 192.168.0.1 flag specifies that the …