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

[Chris Green]

On Thu, Mar 05, 2020 at 03:36:14PM +0000, Chris Green wrote:
> On Thu, Mar 05, 2020 at 09:42:16AM -0500, Ken D'Ambrosio wrote:
> > On 2020-03-05 08:01, Chris Green wrote:
> > > 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?
> > 
> > Your best bet: plug the laptop and the WD box straight into each other, and
> > use Wireshark to sniff traffic (be sure "promiscuous" is set!).  It'll
> > likely do *something* when it comes up, like try to check for an NTP server
> > or something.  The being-plugged-into-each-other is important; merely being
> > on the same switch won't work, as the switch will be smart enough to not
> > send unicast packets on all interfaces, so your laptop won't see them.
> > (There are ways around that, but far easier just to plug straight into each
> > other.)
> > 
> Yes, OK, I wondered if Wireshark might be of some use.  I'll try it,
> thanks.
> 
... and, yes Wireshark showed me what I needed.  There was a short
learning curve and then running Wireshark on the laptop's ethernet
interface connected only to the NAS showed me what I needed to know.
With only the NAS and the laptop there wasn't too much traffic.

-- 
Chris Green