Is there a way to discover what subnet a device is using?

[Chris Green]

I have an old WD My Book NAS which has been sitting on the shelf for
quite a while (i.e. three or four years).  I just wanted to see if the
disk drives in it have anything useful on them still so I powered it
up and I'm trying to 'see' it.

The lights on the front are doing the right sort of thing but I can't
get the reset button to do anything.  It does have custom software in
it so it may be that the reset/power switches don't do what the manual
says they should.

I have of course tried simply connecting it to my main LAN which has a
DHCP server but that hasn't got it working so it seems (if the WD box
is working) that it must have a static IP.

I've tried guessing what LAN subnet it might be set up for and
connecting to my laptop with the same subnet configured statically in
the laptop.  The hardware interface comes up OK, gigabit duplex, but
no actual data connection.  I can't try many subnets this way.

So is there any tool that I can install on my laptop which will try
and get some sort of response from the WD box and help me identify the
IP address?

-- 
Chris Green