wol 0.7.1 seemed to be ignoring the option to restrict the broadcast to a particular subnet and/or doing nothing when that option is specified, but it turned out to be my misinterpretation of the man page:
-h HOST --host=HOST -i HOST --ipaddr=HOST Broadcast packet to this IP address or hostname. This is important if your wol client is a multihomed host and you want to send only to one subnet (default IP address is 255.255.255.255). Using the ip address of the interface (e.g. 192.168.4.1) or hostname there *does not* appear to work. However, sending to the subnet (?) e.g. 192.168.4.0 does do the trick. That is from 4.4-current (GENERIC#1037) with two ethernet interfaces. Regards, -Lars