Forwarding

iptable-forward.md

http://forums.linuxmint.com/viewtopic.php?f=157&t=56226

http://serverfault.com/questions/140622/how-can-i-port-forward-with-iptables

1. Set up the forwarding

    sudo -s
    echo '1' > /proc/sys/net/ipv4/conf/eth0/forwarding
    iptables -t nat -A PREROUTING -p tcp -i eth0 --dport 1521 -j DNAT --to-destination 192.168.56.102:1521
    iptables -A FORWARD -p tcp -d 192.168.56.102 --dport 1521 -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT
   

2. Verify the config

    iptables -L -n
   

3. Persist that config

    iptables-save > /etc/firewall.conf
   

4. Create /etc/network/if-up.d/iptables with:

    #!/bin/sh
    iptables-restore < /etc/firewall.conf
   

5. Make it executable:

    chmod +x /etc/network/if-up.d/iptables