>> The kernel doesn't really have a concept of "aliases", just multiple
>> addresses on an interface.
> 
> But the first one on the list *is* special in a few ways (for example,
> it's the one that gets replaced if you ifconfig an address on the
> interface without saying "alias", and it's the one that gets used as
> the source address of source-not-specified traffic going out that
> interface).

There's also the issue of the broadcast address (or netmask, from a
different point of view), although I must confess I have only a vague
idea what influence it has.

++L