You _used_ to be able to do this (oh, over two years ago?). The address was assigned to the interface, and the error from trying to add a duplicate route was simply ignored, no route got added anywhere. You can figure out when the change was made by examining the code or by seeing when the maillists started to get flooded by people who could no longer do,

# ifconfig if0 inet 10.0.0.1 # ifconfig if0 alias 10.0.0.2

When they meant,

# ifconfig if0 inet 10.0.0.1 # ifconfig if0 alias 10.0.0.2 netmask 0xffffffff

There is a difference, of course - Cisco is perfectly happy to let you do int fa0 ip addr 10.0.0.1 255.255.255.0 ip addr 10.0.0.2 255.255.255.0 secondary I never could understand why this should be impossible in FreeBSD. But I guess this discussion is no longer NANOG relevant :-) Steinar Haug, Nethelp consulting, sthaug@nethelp.no