The networkifs_base_config variable provides a list of network interfaces to use. For logical interfaces, use underscores (_) rather than colons (:). For each interface listed, you provide a group of four variables that defines the netname, netmask, hostname, and IP address for the interface. Use a colon to separate the variables.
The following example shows the content of the networkifs_base_config variable to define two interfaces.
le0 bkp:255.255.255.0:me-bkp:192.168.1.0 hme0 bkp2:255.255.255.0:me-bkp2:192.168.2.0