It was annoying that dhclient would spend 60 second figuring out that eth0 was not connected to a network. Some pre-up lines fixed that problem: auto eth0 iface eth0 inet dhcp pre-up /home/jrennie/usr/bin/check-mac-address.sh eth0 00:50:8B:46:28:6F auto eth1 iface eth1 inet dhcp pre-up /home/jrennie/usr/bin/check-mac-address.sh eth1 00:50:8B:46:28:6F I copied check-mac-address.sh from /usr/share/doc/ifupdown/examples. Jason