autoconnect to wired if link is up

[Stefan Kost <ensonic hora-obscura de>]

hi,

I am on ubuntu feisty and use network manager as I roam around with my  
laptop. On my desk I have a wired connection (static ip), elsewhere  
wifi. Now my problem is that whenever I boot the machine it connects  
to wifi. I checked with ethtool that the link status is readable and  
it works. Any ideas how I can make NM use the wired connection by  
default?

Stefan

# cat /etc/network/interfaces
auto lo
iface lo inet loopback

iface eth0 inet static
address 172.21.42.25
netmask 255.255.254.0
gateway 172.21.42.1
auto eth0