> > i don't see this as being relevant. there won't be anything
> > listening on the interface at this point.
>
> Read it again. *Out* not *in*. Listening is usually done globally,
> sometimes bound to specific *addresses*, rarely bound to specific
> *interfaces*. That has nothing to do with the issue at hand.
In 2.1/2.2 kernels, both incoming and outgoing packets are sent through the
routing engine. Therefore, for a interface to function correctly, there must be
multiple routes set up -- an outgoing route, a local route for its address and
a broadcast route.
By assigning an address to the an interface, you just tell the kernel to add
a local route to this interface. Local routes without interface addresses or
interface addresses without local routes are semantically incorrect.
By attaching a network to the interface (i.e, by specifying a non-trivial
netmask), you tell the kernel to add an outgoing network route and also a
broadcast route through the interface. Again, attached networks without routes
or vice versa are semantical nonsense.
Have a nice fortnight
-- Martin `MJ' Mares <mj@ucw.cz> http://atrey.karlin.mff.cuni.cz/~mj/ Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth "What? DosShell wasn't supposed to be a joke?"- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/