auto eth0:0
iface eth0:0 inet static
        address new.secondary.IP.here
        netmask 255.255.255.255

        # for eth0:0 
        post-up /sbin/ifconfig eth0:0 new.secondary.IP.here netmask 255.255.255.255 broadcast new.secondary.IP.here
        pre-down /sbin/ifconfig eth0:0 down