Hi,
I just fixed a bug in xennetback (the xvif interface), that could explain your
problem. Can you try a newer kernel (the changes applies fine to netbsd-3,
I will request a pullup in a few days) if this is till a problem for
you ?

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
     NetBSD: 26 ans d'experience feront toujours la difference
--