Setting up aliases on an interface

# ifconfig dc0 inet alias 192.168.36.131 netmask 255.255.255.255

# cat /etc/hostname.dc0

inet 192.168.36.130 255.255.255.0 media 100baseTX
inet alias 192.168.36.131 255.255.255.255
inet alias 192.168.36.132 255.255.255.255

# . /etc/netstart

# ifconfig -A
lo0: flags=8049 mtu 33224
        groups: lo
        inet6 ::1 prefixlen 128
        inet6 fe80::1%lo0 prefixlen 64 scopeid 0x4
        inet 127.0.0.1 netmask 0xff000000
pcn0: flags=8843 mtu 1500
        lladdr 00:0c:29:8b:f2:65
        groups: egress
        media: Ethernet autoselect (autoselect)
        inet6 fe80::20c:29ff:fe8b:f265%pcn0 prefixlen 64 scopeid 0x1
        inet 192.168.36.130 netmask 0xffffff00 broadcast 192.168.36.255
        inet 192.168.36.131 netmask 0xffffff00 broadcast 192.168.36.255
        inet 192.168.36.132 netmask 0xffffff00 broadcast 192.168.36.255
        pflog0: flags=0<> mtu 33224
enc0: flags=0<> mtu 1536