virtualbox.org

I have a Windows Xp , Vbox 2.1 and a ubuntu 8.10 guest.
The guest can ping the host and all other devices but no one can ping the guest. The guest has internet connection established so that one works. But why cant sb ping the guest? There is supposed to be no port blocking on any port

If you don't say what network type you are using, we can't help you. If you use NAT, it's obvious that you can't ping the Guest, it's on an entirely different network. Please read up on what NAT really is.
If you want connectivity to the Guest, you need to use Host Interface Networking. See the manual for how to get it working (should be self explaining now if you look at the settings).

It works.

Great! Thank you