Current IP configuration:

	# ifconfig -a
	
	lo0: flags=2001000849 mtu 8232 index 1
			inet 127.0.0.1 netmask ff000000 
	ce0: flags=1000843 mtu 1500 index 2
			inet 192.168.70.20 netmask ffff0000 broadcast 192.168.255.255
			ether 0:3:ba:ca:f0:3e 

Add IP alias:

	# ifconfig ce0:1 plumb
	# ifconfig ce0:1 192.168.70.21 netmask 255.255.255.0 up

Enable of boot:

	# vi /etc/hostname.ce1
	hostname-21

Add to host file:

	# vi /etc/hosts
	192.168.70.21	hostname-21