knoppix 5.0.1 on HDD and DHCP

I lately switched from knoppix 4 to knoppix 5 and, prior to installing it on my hard drive, I configured eth0 with dhcp on the local network while running on the live CD.
Now, when booting from HDD, eth0 is configured if I am connected to the very same network I was connected to during the installation. When connected to any other dhcp network not only eth0 is not up, but netcardconfig does not work either. I have to manually give a static IP (ifconfig) and a default router (route add default gw ...) to get eth0 working.
/etc/network/interfaces looks correct
/etc/network/ifstate is replaced by /etc/network/ifstate.hotplug but I hadn't checked if it was already so when running a Debain comig from knoppix 4
So how does my Debian know what its first local network was? Is there a place where the orginal dhcp server could be 'hard-wired'?

Your post has been moved to the HD install forum from networking because, while there is some overlap, it is pretty clearly a problem created by the hard disk "install". If it's any comfort this is not the only networking problem seen after trying to do a Knoppix install, but if anyone can help you I expect it will be miore likely to be the people here than the people who avoid this forum.

I found the answer by chance, trying to configure my routers for video on IP.
The provider interface used to be a mere ADSL/Ethernet convertor and my Ethernet/Wifi router had got a public IP.
The last upgrade of that box is a real router get a public IP. My Wifi router gets a local IP on 192.168.1.0 from that box.
My local network is 192.168.0.0. The dhcp request from my knoppix laptop was redirected by my Wifi router (in spite its being a dhcp server for 192.168.0.0) to the ADSL router, which answered by giving an IP on 192.168.1.0. But that answer stayed stuck in the wifi router.
I still don't understand why the wifi router transmitted the dhcp request in the first place.
By now everything works by downgrading the wifi/Ethernet router to a wifi/ethernet hub.