related to port forwarding in VirtualBox Host ->Guest

Question

I have WindowsXP as GuestOS inside VirtualBox running on Ubuntu 8.10. I am able to use Netmeeting inside WindowsXP (Guest) and connect to other machines in the intranet.

Netmeeting listens to the ports 1503 and 1720 (among other ports).

Now I would like to know how I can connect to the Netmeeting which is inside VirtualBox from a machine on the intranet. THe Guest OS has only NAT translated IP address (10.0.2.15).

VirtualBox provides a way to forward ports using VBoxManage. But my question is, in the Host OS, no application is listening to the ports 1503 and 1720. This being the case, how can I forward a request coming to Host:1503 -> GuestOS:1503 ? Should I use any dummy listeners to listen to 1503 and 1720 so that they ports are"open"?

Answer 1

You need to alter your firewall scripts and add DNAT rules for the ports in question. You should not have anything listen on those ports on the host OS, that will prevent any packets to those ports from reaching the guest if you didn't perform the DNAT, and will be useless if you did because the kernel will never send anything to them.