This sounds reasonable, modulo that dhclient is still responsible for
cycling between TP, coax and AUI on wired nets.   I'm trailing edge
and I have only TP now, so that's probably ok.   But perhaps the
'wifid' should do that for all interfaces, not just TP.

	Enhance dhclient to know about interface priorities -- run
	DHCP on an interface if and only if there are no higher-priority
	interfaces that respond properly to the protocol.  If a higher-
	priority interface should suddenly appear or suddenly respond,
	unconfigure the IP address from the lower-priority interface.
	(That one is a bit tricky -- you may have open connections.
	At least, the default route should be taken away from the
	low-priority interface.)  The essential point is that dhclient
	should -- or at least could -- get out of the carrier-finding
	game on wireless nets, and should become cognizant of carrier
	on all interfaces.

The old address should stay, but I think dhclient is currently not
set up to deal with conflicting default route choices.   This
shouldn't be that hard.   It could also check for PCBs bound to that
addr, and if none, stop using it.

-- 
        Greg Troxel <gdt@ir.bbn.com>