how to debug dhcp?

[dragoran]

hello
when I try to use dhcp for my network device (eth0 - forcedeth) it does 
not get an IP with the result: failed
Using a static IP adress works; same for using dhcp on windows.
I hav disabled the firewall to make sure that it does not gets blocked...
so my questions are:
1) any ideas what could be wrong?
2) how can I debug it to find out what is causing it?
a message like "failed" is not helpfull at all ...