More specifically: an openwrt derived setup (wifi pineapple).

I'm trying to use my n900 as 3G link and failing. My laptop dists make this too easy (click, click, done).

When I connect the n900 it shows up as cdc_ether device and in ifconfig there is a usb0 device.

Next I tried to dhcp to get an IP address, but that never gets one.

Is DHCP the way to go? Any pointers on what to do next are welcome!

OK, I found http://wiki.maemo.org/N900_USB_router so the standard pc suite mode is not enough it seems.

Now the DHCP client on the other side gets an IP, but pinging the n900 fails

You could try qtmobilehotspot package, it lets you configure an hotspot via wifi or an USB-connected link to your N900. This is a more simple setup, may be not that powerful like the manual setup, but works just fine.

I have never managed to get (qt)mobilehotspot work properly. Qtmobilehotspot does wifi only and loads of stuff has problems with adhoc mode. And it makes my n900 reboot sometimes.
Mobilehotspot does know USB sharing, but it also tends to make my n900 reboot.

Might be related to KP and/or CSSU-thumb, but the n900 is otherwise rock-stable.

And anyway, for a USB connection most of the stuff is already there, my laptop and netbook connect perfectly in pc-suite mode.

Just looking to get that working on a non-GUI and non-networkmanager platform...
Plan is to have the wifi pineapple act as my mobile hotspot regardless of wifi client or 3G connection, and tunnel everything via sshuttle to my home network.