To first order, ignoring loopback addrs is sensible.   But it doesn't
fit the pattern of configuring a secondary, or locally-hosted virtual
address on lo0.  So perhaps a 'this is a real routeable addr' flag is
in order.  Or, perhaps only the first loopback address should be
ignored, but that feels kludgy and likely to lead to problems, since
it makes unwarranted assumptions about which addresses are routable.

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