It seems the point is being missed here. The issue is that "allow-hotplug eth0" does *not* work while "auto eth0" does work! If "allow-hotplug" is used then "dhclient" has to be run manually in order for eth0 to get its IP related settings. This seems to be a bug. Greg since you started this thread then you can file a bug against "interfaces". Install and run "reportbug". Just follow the instructions.