I use a hub/switch connected to the mandrake pc to connect to internet.
I have a dynamic ip so I connect through PPPoe.
1.Go to network connections
2. Add new connection
3. Say LAN connecton and assign an ip (192.168.0.xx) to the mandrake PC.
4. Restart the network.
5. Go back to network and do a add connection again.
6. This time choose PPPoe(Or which ever is appropriate for you internet connection).
7. Enter ur user name and password for the connection.
8. Restart the network connections when prompted.
9. Open Network connections --> monitor connections.
10. Verify that both upstream and downstream are looking good.
This is how I set it up and it works for me