When you run ifconfig inet x.y.z.a netmask 0xffffff00 alias x.y.z.b the kernel picks up x.y,.z.b as a broadcast adres. Whenever you also specify the broacast adres, it work as expected. Fix: This is no bug. alias is just a flag for the complete command line. Not an option that comes with an adress .
State Changed From-To: open->closed This was a non-bug