Network interface sanity

[Andreas Ehn <ehn@kth.se>]

Hi,

I have a laptop with one wired ethernet interface (eth0) and one
wireless interface (eth1). I'm using ifupdown.

When the computer is not connected to a wired network, while starting
up, it is associated with my wireless network and requests and receives
an IP address with DHCP.

That, however, doesn't satisfy the machine. It proceeds by requesting an
address for the wired network as well, despite there being no attached
network cable, which holds up the boot process until the DHCP client
times out and gives up.

What I would like to happen in this situation is that the machine would
only try to get an address over the wired network interface if it is
actually connected to a network. Otherwise it should try the wireless
interface directly.

Iff connected to a wired network, the system should only try to connect
to a wireless network after having failed to acquire an IP address from
the wired network.

I would like all of this to happen automatically.

Is it possible to configure /etc/interfaces like this? Reading
interfaces(5) and the examples in /usr/share/doc/ifupdown didn't help
me.

Thanks,
Andreas