maemo.org - Talk - USB connection interrupts wifi access on host debian PC

I'm goin' nuts, have been messing with this for hours now, and though I think it's something stupid, can't figure out what I've messed up...

I just wanna achieve the following: my Debian PC is connected to the internet over a Wifi connection. Wanna plug in the N900 with the USB cable and ssh access it.

Had it working easily, don't know what's changed.

Basically now, as per:
http://wiki.maemo.org/N900_USB_networking
http://wiki.maemo.org/USB_networking..._Configuration
and
http://pc-connectivity.garage.maemo....00000000000000

I've added to /etc/network/interfaces on the PC:

Code:

auto usb0

allow-hotplug usb0



mapping hotplug

script grep

map usb0



iface usb0 inet static

   up iptables -t nat -A POSTROUTING -s 192.168.2.15 -j MASQUERADE

   up echo 1 > /proc/sys/net/ipv4/ip_forward

   down iptables -t nat -D POSTROUTING -s 192.168.2.15 -j MASQUERADE

   down echo 0 > /proc/sys/net/ipv4/ip_forward

Now, when I plug in the USB cable, ifconfig gives me for USB:

Code:

usb0      Link encap:Ethernet  HWaddr 12:5e:6e:98:55:a5  

          inet6 addr: fe80::105e:6eff:fe98:55a5/64 Scope:Link

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:0 errors:0 dropped:0 overruns:0 frame:0

          TX packets:21 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:1000 

          RX bytes:0 (0.0 B)  TX bytes:3525 (3.4 KiB)

and I can ping google.com no prob. Can't ping 192.168.2.15

The moment I run

Code:

# ifconfig usb0 192.168.2.14

I can ping 192.168.2.15 but pinging google.com gives me, after a couple of secs wait:

Code:

ping: unknown host google.com

After unplugging the USB, all goes back to normal.

WTF? What am I missing?