I want to forward a PORT from my HOST computer (Slack 11) to my guest Virutal Computer(WinXP), for a application I've created and needs an forwarded port to work properly.
But I have no idea how to do this.

In VBox settings under networking I have selected NAT, if I try to select Host interface, it asks me for interface, ok, ra0.
And an init and term application, what would I have to input there?
Oh, the guest computer has a manualy configured IP, 10.0.2.15 and it's gateway is 10.0.2.2.
When I try, from the guest, to i.e. ping the host(10.0.2.2) it pings corectly, if I try to access FTP from my guest on my host it works also.
But when I try to ping 10.0.2.15 from the host it doesn't work.
If I try to forward a port to 10.0.2.15 i.e.:
iptables -t filter -A FORWARD -p tcp --dport 3309 --syn -m state --state NEW -j ACCEPT
it doesn't work.