On Wed, Mar 21, 2012 at 12:57 PM, Worley, Dale R (Dale) <dworley@xxxxxxxxx> wrote: >> From: Craig Finseth [snark17@xxxxxxxxx] >> >> You've just rediscovered what the "link local" part of the link-local >> address means: the address is local to the link! It is not globally >> unique or even unique within a host, it is just unique within a link. > > Actually, it's globally *unique*, because it contains the MAC address. > The problem is that it's not *routable*, even within the context of a > single host. And unless you give an application on the host guidance, > it depends on host-context routing to get its output packets to the > correct wire. It's hard to remain aware that host-context routing is > important, because it's almost always work. Well, it's globally unique to a host, not to an interface: the host (in general) uses the same link-local address on all interfaces. Thus, you can't tell from the address which interface it refers to. -- Craig A. Finseth