Internet connection disappeared after debian-install on laptop

[Vegard L. Rekaa]

Hi list,

I'm installing Debian Etch (with netinstall-cdimage) on a laptop. During installation, it configured the DHCP-internet-connection automaticly, downloaded all 708 packages and installed them perfectly.

But, when I reboot the system after intall, the internet connection is gone. I checked with another computer, that the line out is OK, but still when I plug the (ADSL) modem to the laptop, internett is not available.

I'm not experienced with internett-connection setup, so I must ask:
 1. Wich commands gives output that makes it possible to locate the error?
 2. Is there a way to repeat the auto-configuration I saw during installation after the system is up and running?
 3. Any other advices or hints are very much welcome!

System specs:
- The internet connection is broadband, with dynamic IP-adress (ADSL through the telephone-line).
- No password or login nescesarry.
- Debian Etch (testing) kernel 2.6.15-486
- Laptop has no internal network-device, but has one available when connected to the docking station (wich of course is connected).

Cheers, Vegard